Weight loss success: nutrient dense foods cut calories and control hunger

When it comes to maintaining or reducing body weight, the key to long term success is to choose foods with a low energy density. What is energy density in foods? The Center for Disease Control defines it as “the amount of energy or calories in a particular weight of food.” This is generally represented as the number of calories in a gram (kcal/g). This brings me to the law of thermodynamics, or energy balance equation, which I’ve discussed in a past post here.

Energy balance - Understanding this concept is important to successful weight loss, gain or maintenance.  So, here’s a brief review: if you consume more calories than you burn, you will gain weight. If you burn more calories than you consume, you will lose weight. However, a big caveat: while a calorie is a calorie, the nutrients you consume affects metabolic and hormonal secretions which may cause you to store fat instead of utilize the fat for energy, and vice versa. The types and varieties of food and beverages you ingest effect weight management, but more importantly, they are essential to your total wellness.

Understanding caloric need - Exercise is a variable that increases caloric expenditure and metabolism. In order to determine an estimation of the calories you need to consume to gain, maintain or lose weight, it's helpful to calculate your total daily energy expenditure (TDEE). You can use the calculator found here, which calculates basal metabolic rate (BMR) using the Mifflin-St Jeor equation, and then applies an activity multiplier. It's best to underestimate your acitivity level when using the calculator if you're looking to lose weight because this puts you on the conservative side of daily caloric needs. Then, if you want to calculate how many calories you should eat daily to achieve weight loss at a steady, healthy pace, you subtract 15-20% from your TDEE number. Conversely, if you're looking to gain weight, add 15-20% to the TDEE. It's not recommended that you subtract more than 25% from your TDEE calculation. You don’t want your calorie intake to drop to an unhealthy and unsustainable level.

The amount of calories you eat is important, but not the whole picture in a healthy diet. Good nutrition includes a balance in the macronutrients listed below and the way you accomplish this is in the way you combine the foods you eat in a meal. For example, rice and beans.  These two foods are considered a complete protein when eaten together. If you're a vegan. In general, try to get your total daily caloric intake from a variety of whole foods as follows: 

• Protein: 1 gram per pound of body weight
• Fat: .45 grams per pound of body weight
• Carbs: The remaining number of calories left will be filled with carbs

Nature counts the calories – Back to our discussion of low energy dense foods and how they help with weight loss.  It seems Mother Nature really does know best because “foods with a lower energy density actually provide fewer calories per gram than foods with a higher energy density (CDC).”  Also, low energy dense foods are typically more nutrient dense. Nutrient density is a measure of the nutrients provided per calorie of food, or the “ratio of the amount of a nutrient in foods to the energy provided by these same foods (Nestle).”

So, it’s a win/win situation when you choose low energy/high nutrient dense foods because not only do they contribute fewer calories to the energy balance equation, they also provide greater nutritional value per calorie, which is especially beneficial for our health. These foods are the best of both worlds so to speak. 

Let’s look at a simple example of a higher nutrient/lower energy density food and a lower nutrient/higher energy dense food containing the same amount of calories per serving:   

	Nutrient Dense	Energy Dense
171 calories/serving	2 wedges of watermelon (approximately 1/8 of a whole watermelon)	14 ounces of Dr. Pepper
Nutritional Facts per serving	Calories 171 Calories from Fat 7 Total Fat 0.743g Saturated Fat 0.371g Polyunsaturated Fat 0.371g Monounsaturated Fat 0.371g Cholesterol 0mg Sodium 7mg Potassium 636mg Carbohydrates 43.086g Dietary Fiber 2.229g Sugars 35.286g Protein 3.343g Vitamins & Minerals: Vitamin A 67% · Vitamin C 78% Calcium 4% · Iron 7%	Calories 175 Calories from Fat 0 Total Fat 0g Saturated Fat 0g Polyunsaturated Fat 0g Monounsaturated Fat 0g Cholesterol 0mg Sodium 70mg Potassium 0mg Carbohydrates 46.2g Dietary Fiber 0g Sugars 44.8g Protein 0g

Arguably, it might not seem equitable to compare a beverage with a food, but watermelon is 91% water by weight, so it's not too biased of a comparison. Remember, we are comparing identical calories per serving here. The numbers speak for themselves. If I’m trying to consume fewer calories in an effort to lose weight, watermelon is the better food choice by far. Where’s the Vitamin A and C in the soda? The numbers indicate a lot of sugar, no fiber or protein. The soda simply contains what are referred to as "empty calories" which provide energy, but no nutrition.  So after I drink my soda my body gets an injection of simple sugars and a blast of salt. Ironically, the salt can make me thirsty and this leads me to drink another soda later, but that's for another post!

On the other hand, the 2 wedges of watermelon provide 67% of the daily requirement of Vitamin A and 78% of Vitamin C.  That’s some good stuff! Plus, the 2.3 grams of fiber in the watermelon will help me feel fuller for a longer period of time than the soda, which has 0 grams of fiber. I might even feel full after eating 1 wedge of watermelon. Therefore, I can eat less of this food and decrease my calorie intake while keeping my hunger satisfied for longer than I could with a soft drink. This brings me to my next point, which can be pivotal to weight loss success.

Eat more to lose weight? – Really?! Usually losing weight is equated with starving oneself and eating minuscule portion sizes, right? However, foods with a low energy/high nutrient density typically contain fewer calories per serving than the same amount of a high energy/low nutrient density food and they provide more vitamins, minerals and also phytochemicals. You can read more about phytochemicals and their amazing health benefits here. 

Now, let’s look at another example comparing the nutritional information for servings of an nutrient dense food with a calorie dense food, but of differing calorie content:

	Nutrient Dense Food	Energy Dense Food
Food choice	Kale	French Fries
Calories per serving	1 cup chopped 33 calories	1 medium serving (117 g) 365 calories
Nutritional facts per serving	Total Fat 0.6 g    Saturated fat 0.1 g           Polyunsaturated fat .2 g               Monounsaturated fat 0 g              Cholesterol 0 mg              Sodium 25 mg    Potassium 329 mg            Total Carbohydrate 6 g   Protein 2.9 g Vitamin A 133% Vitamin C 134% Calcium 10%      Iron 5% Vitamin D 0%      Vitamin B-6 10% Vitamin B-12 0%               Magnesium 7%	Total Fat 17 g     Saturated fat 2.7 g           Polyunsaturated fat 6 g   Monounsaturated fat 7 g              Trans fat 0.1 g    Cholesterol 0 mg              Sodium 246 mg  Potassium 677 mg            Total Carbohydrate 48 g Dietary fiber 4.4 g            Sugar 0.4 g          Protein 4 g          Vitamin A 0% Vitamin C 9% Calcium 2%         Iron 5% Vitamin D 0%      Vitamin B-6 20% Vitamin B-12 0%               Magnesium 10%

Once again, the data doesn’t lie. As the above comparison shows, I would have to eat a whopping 11 cups of chopped kale to equal the amount of calories I would consume in a medium serving of fries! If I’m trying to lose weight, the good news is that I can eat more kale while consuming far fewer calories than I would if I were to eat the French fries. This means I will feel fuller for a longer period of time. I’m also fueling my body with less unhealthy fats and far more nutritional value. Like I said before, it’s a win/win.

Move over vegetarian, I'm a nutritarian -  So are you ready to transition to a nutritarian diet which is eating more low-energy/nutrient dense foods? If you said yes, congratulations! You're making a good choice for your health. Are you unsure how to decide which foods to choose? A good starting point to help you in your search to find the most nutrient dense foods is to check out the ANDI guide. ANDI stands for aggregate nutrient density index and was developed by Dr. Joel Furhman.

This is from Dr. Furhman's site: "Adequate consumption of micronutrients – vitamins, minerals, and many other phytochemicals – without overeating on calories, is the key to achieving excellent health. Micronutrients fuel proper functioning of the immune system and enable the detoxification and cellular repair mechanisms that protect us from chronic diseases. A nutritarian is someone whose food choices reflect a high ratio of micronutrients per calorie and a high level of micronutrient variety."

With this in mind, the ANDI guide categorizes whole foods and then scores them on a scale from 1 to 1000 based on an extensive range of micronutrients, including vitamins, minerals, phytochemicals and antioxidant capacities. In addition, Dr. Furhman's original ANDI guide has been updated to reflect a more accurate picture of each food's nutritional qualitywhich now considers certain beneficial phytochemicals, such as angiogenesis inhibitors (i.e. cancer prevention, read more here), organosulfides (found in onion, garlic and cruciferous veggies), isothiocyanates (organosulfur compounds found in cruciferous veggies and are among the most effective cancer-prevention agents known), and aromatase inhibitors (suppress the synthesis of estrogen and thought to aid in the prevention of breast cancer).

The ANDI guide can be a useful tool in your determining healthy food choices, but it isn't the holy grail. I like what Dr. Furham says and I believe his suggestion is the best advice when it comes to choosing foods.  He says: “…nutrient density scoring is not the only factor that determines health benefits… if we ate only foods with a high nutrient density score, our diets would be too low in fat. For that reason we have to pick some foods with lower nutrient density scores.” Also, he notes that if thin individuals or those who are very active ate only foods with the highest nutrient density, they would become so full from fiber that it's likely they would be unable to meet their caloric needs. Remember my kale example above? One can only eat so much fiber. Balance and variety are key to consuming the greatest number and variety of micronutrients.

You may already know that kale is a better food choice than French fries, so if you operate on the simple premise that your diet should emphasize fruits, vegetables, and whole grains and not prepackaged, processed or fast food, you probably don’t need the ANDI guide to tell you where to get the most nutritional bang for your buck. However, if you’re uncertain as to whether or not you’re making the best food choices for your health, the ANDI rankings are a good starting point. 

I really like Dr. Weil's anti-inflammatory "diet" approach and I have incorporated some of his wisdom into my lifestyle as well. I've blogged about the health benefits of reducing the risk for chronic inflammation in an earlier post. Look for more on that in a future post.  In the meantime, I'll leave you with this food for thought:

Sources:

• CDC Low energy dense foods and weight management - http://www.cdc.gov/nccdphp/dnpa/nutrition/pdf/r2p_energy_density.pdf
• Nutrient Density, Clemson Cooperative Extension - http://www.clemson.edu/extension/hgic/food/nutrition/nutrition/dietary_guide/hgic4062.html
• Food and Nutrition, Nutrient Density - http://www.nestle.com/asset-library/Documents/Library/Documents/Nutrition_Health_Wellness/Food-and-Nutrition-Issue09-Nutrient-Density-Jan2008.pdf
• Sports Science Exchange, Energy Balance and Weight Reduction - http://www.uni.edu/dolgener/UG_Sport_Nutrition/Articles/Energy_Balance.pdf
• Simple Science Fitness, Energy balance and law of thermodynamics -http://simplesciencefitness.com/ 
• Whole Foods Market uses ANDI guide - http://www.wholefoodsmarket.com/healthy-eating/andi-guide
• Nutrient Rich, ANDI Guide - http://www.nutrientrich.com/1/aggregate-nutrient-density-index-andi-score.html

Increase weight loss by working out less?

Really? -
Judging from the ever rising overweight/obesity rates in the United States, I think it's safe to assume that a majority of Americans subscribe to the work out less plan. I find it a bit alarming when scientific data is released and the news takes a portion of a study's findings out of context and reports on it. Typically we can end up misguided and confused. That's why it's so important to understand the bigger picture surrounding "sound bites" like this post's title. This reminds me of a radio ad that would, ironically, air while I was training at the gym.  The advertisement was pushing a diet pill which promised weight loss without the "unhealthy stress and strain of exercise"! I'll spare you a rant, but I will say that the ad was eventually changed so that it did not include the word unhealthy.  Calling exercise unhealthy is blatantly inaccurate. Yet, unfortunately this isn't obvious to everyone. But I digress...

What's going on? -
Saying that we can increase weight loss by working out less is ambiguous because this statement tells only part of the story. So, before you scratch that workout off your to-do list, please read on. According to a study published in the American College of Sports Medicine's (ACSM) Journal of Medical Science and Sports Exercise, it's possible to burn more calories and spend less time working out. However, the key to this result lies in how intensely you workout. Before I go on, it might be helpful to recall the caloric balance equation and its role in weight maintenance, and you can read more about this in a past post found here.

Image from CDC website

Consider a typical day of food consumption and energy expenditure. Simply put, if calories eaten exceed calories burned, we end up with a calorie surplus for that day and over time this leads to weight gain. On the other hand, if we burned more calories than we ate, than over time this leads to weight loss. If  calories in are equal to calories out, the scale is in balance and weight is maintained. Another thing to keep in mind is that we are always expending energy, even while we're resting.


Back to the study - The researchers wanted to see what the energy expenditure at rest of males, aged 22 to 33, would be on a day when they performed a vigorous indoor cycling exercise bout vs. on "a controlled resting day" when they performed no exercise at all.  I underlined and bold faced the word vigorous because this is very important to note. In this case vigorous exercise is defined as performing a physical activity at a level that causes you to be too out of breath to talk. Working out at this intensity level "resulted in a significant [emphasis added] elevation in post exercise energy expenditure, that persisted for 14 hours" after the exercise bout ended (ACSM).


Wow! This sheds some much needed light on that rather ambiguous statement that implies we can increase weight loss by working out less. Now we understand that it's possible to decrease the amount of time we spend working out, but this must be accompanied by an increase in the intensity of our workout to a vigorous level. This is because the research suggests that we can burn additional calories above and beyond what we burned during the workout, even while we're at rest! This is sometimes referred to as caloric after burn.

Here's the data: During the vigorous cycling bout these guys expended 520 calories (kcal).  This isn't surprising because we all know exercise expends calories. We also know that vigorous exercise burns more calories than low and moderate intensity exercise. However, what is really exciting is that after the men finished exercising, and with their post exercise activity level restricted and monitored, they continued to  burn an additional 190 calories (kcal)  during the 14 hours after their workout, as compared with control days when the men were inactive. "The 190 calories burned after exercise above resting levels represented an additional 37% to the net energy expended during the 45-min cycling bout." 

Bottom Line - 
The study's test subjects were young men, so the results may not be the same for women, or for an older population.  Also, we might not be able to workout at a vigorous level for 45 minutes. Given this and other studies on vigorous intensity exercise which show the added benefit of caloric after burn, it seems beneficial to try to incorporate little bouts of vigorous intensity exercise in our workouts. But if you've never exercised, or haven't worked out in years - BEGIN SLOWLY and always consult your physician before beginning any exercise program. Obviously any exercise is better than none, but I like the idea of putting in a little more effort, giving it a little less time and reaping bigger rewards from my workout.  It seems like a win/win to me and that's no sound bite.

In the next post there will be some suggestions for vigorous intensity bout exercise programs and also a discussion relating to another study that shows bouts of vigorous intensity exercise have been shown to be beneficial in reducing inflammation in overweight and obese men. Chronic inflammation is linked to all kinds of health problems.

In the meantime, keep moving! 

Sources
CDC - http://www.cdc.gov/obesity/data/trends.html
ACSM - American College of Sports Medicine - http://journals.lww.com/acsm-msse/Abstract/2011/09000/A_45_Minute_Vigorous_Exercise_Bout_Increases.6.aspx
CDC - http://www.cdc.gov/healthyweight/calories/index.html
chronic inflammation -  http://www.drweil.com/drw/u/ART02012/anti-inflammatory-diet

Try a new f-word while exercising - FUN!

How's that New Year's resolution you made to exercise coming along? Maybe you've doubled down on your efforts, but are wondering if it's really worth it. Why does something that we know is good for us and that seemed so exciting just a few weeks ago, turn into a lackluster chore we begin to avoid? Rather than dreading it, slugging it out half-heartedly or abandoning your goal altogether, how about considering a different strategy? Try putting a little fun in your exercise program!

Yes, you read that right. FUN! Okay, so, maybe for you another F-word comes to mind when thinking about exercising, but, before you discount the idea as absurd, think about it for a minute... Can exercise really be fun and if so, what could make it fun? I think our response to this question might be influenced by our past experiences with physical activities.  Reflect back to when you were a kid. Did you ride a bike, a skateboard, or a scooter? Did you play tag, hide and seek, jump rope, and run races? What about shooting hoops, roller-blading or hula-hooping? You get the idea. These are all physical activities that for most of us are associated with fun. Now, what comes to mind when you think about your next workout on the treadmill, elliptical trainer or recumbent bike? If you said fun, good for you, but you're definitely in the minority.

The bottom line is for many of us is that physical activity has lost this element of fun. So, if your wondering why you're struggling with waning motivation, or you've moved past that stage to just giving up altogether, take a look at your workout and ask yourself - is this fitness routine boring and uninspiring? Case in point, faced with taking the stairs or the escalator, which would you choose? Well, not surprisingly, an experiment conducted by Volkswagen found that the majority of people would use the escalator - that is until they made the stairs fun.  Check it out:

 

The Fun Theory

 If you're wondering, how do I make my workouts fun?  Here are a few suggestions:

1. Revisit some of the childhood activities you once liked to do, although you may have to scale them back to accommodate your current fitness level
2. Know what you like and reward yourself for doing it. If you find being outside exhilarating, than choosing a form of indoor exercise isn't going to work for you.  Consider hiking through a local park, planting a garden or walking the dog.  Commit to it and reward yourself when you reach a predetermined goal. See SMART goals post here on how to set specific, measured, attainable, realistic and time-targeted goals, another key to being successful.
3. Progress g r a d u a l l y. This prevents pain and injuries. Remember, we had to learn to crawl before we walked. This applies to everyone. Even if you were a super athlete in college. If you've not exercised in a few years - you need to take it slowly. A few words about exercise and pain. Now, don't get me wrong, there will be a measure of discomfort, but this isn't pain and it will decrease over time. Exercise shouldn't be torture.  The old "No pain no gain" thinking has been replaced with the much wiser - "Train, don't strain."
4. Mix up your activities.  Variety is the spice of life, so they say and in this case it helps to prevent overuse injuries, as well as boredom and monotony.
5. Enlist the help of a buddy. Exercise is more fun if you have the support of a like minded friend. Mutual encouragement is a wonderful motivator.
6. Make exercise less like a "routine" and more like a game - a mental game that is.  Set a little "contest" for yourself for each physical activity you undertake.  For example, today when I perform the plank I'm going to hold this position for 10 extra seconds.  Make this  mini-challenge attainable, but not too easy, and then make sure you congratulate yourself when you win. 

Of course, always check with your physician before beginning any exercise program.

So, are you ready to stop cursing those dreaded workouts and put some fun back into fitness? Just give these ideas a try and perhaps you'll find a new attitude about your exercise resolution. You've got nothing to lose, right? Well, except maybe the few pounds you've resolved to lose already.   I look forward to hearing all your success stories. Happy new year!

References
Association for Applied Sports Psychology - Exercise Adherence - http://www.appliedsportpsych.org/Resource-Center/health-and-fitness/articles/exercise-adherence
The Fun Theory - http://thefuntheory.com/

Am I burning fat? Aerobic exercise & energy use

Now that we have a general understanding of the energy balance equation which was discussed in last week's post found here, let's focus on how this all relates to something commonly referred to as the fat burning zone. You may have seen this zone, along with the cardio zone, illustrated on the treadmills, elipticals or aerobic exercise heart rate charts at your fitness center or gym. These zones are based on aerobic training principles and in theory are true, but in application can be somewhat misleading.

Basic Principles of Fitness Training-

If one of your fitness goals is to lose weight, you might be thinking that the fat burning cardio workout listed on your treadmill is the way to go. However, before we look at the fat burning zone specifically, I want to highlight a few basic principles of fitness training first. In order to put together an effective exercise program we need to address:

1. Overload - Overload is the amount of stress or demand that we put on our body during exercise. In order to improve our level of fitness we need to challenge our bodies during our workouts by increasing our level of effort. The amount of overload effects the level of intensity of our workouts and this in turn influences the improvements in our fitness level. If we work out too easily we are likely to see little change in our fitness level, whereas too much overload can lead to injury or burn out.(3)
2. Progression - The human body has the amazing capacity to adapt to the demands of exercise by improving its functioning. Because of this ability it is essential to make changes to your workout after you notice that the current level you're working at is becoming too easy. This isn't always a simple assessment, nor is it something many people want to do.  We get comfortable with a routine, so it is easy to become complacent.  This is why many people plateau, or find themselves at a point where they see little to no change in their fitness level (3).

Now that we understand two core principles of fitness training, we need to know how to apply them. When putting together a workout we now know that we must consider the amount of overload needed to maintain or improve our particular level of fitness and for a specific fitness component.  In this post, for example, we're looking at improving our cardiovascular fitness level and body composition by doing aerobic exercise. In order to address the progressive overload principles we must consider 4 areas that are represented by the acronym FITT, which stands for:

• Frequency (how often we perform the activity)
• Intensity (how hard we are challenged by the activity)
• Type (mode of activity)
• Time (how long/duration of the activity) (4)

I prefer the acronym FITTER - which adds Enjoyment and Rest into consideration as well. Adherence to an activity is more likely if it is enjoyed. Arguably more important is the balance between exercise and rest. Too much of a good thing is possible with exercise.  Having said that, over training is something I rarely see.  In fact, the opposite is more often the case.

So, at this point you might be wondering what all this has to do with the fat burning zone. Well, what the fat burning zone is referring to is the level of intensity, along with the amount of time an aerobic activity is performed at, and the macronutrient (fats, carbs, proteins) energy sources used by the body to accomplish the task. By the way, if you're curious to know what exactly constitutes an aerobic workout you can read more here, and if you'd like to catch up on our discussion of energy sources from last week you can find that here.  Now, this bring us to the three energy systems utilized by the body during physical activity. 

Physical Activity and the Three Energy Systems-

As discussed last week, in order to function our bodies need energy in the form of food. We get this fuel from the carbs, fats and proteins found in what we eat and drink. However, the amounts of  these macronutrients the body uses for energy vary depending on the type of activity we're performing.

1. For immediate, explosive energy needs the body uses the immediate energy system. This system fuels activities that last for about 10 seconds or less.
2. For high intensity acitivities lasting for about 10 seconds to 2 minutes the body uses the nonoxidative (anaerobic) energy system. 
3. For any activities lasting longer than 2 minutes the oxidative (aerobic) energy system kicks in. (3)
   

It's important to note that the body typically uses all three energy systems when we exercise, or in activities of daily living (3).  "The intensity and duration of the activity determines which system predominates" (3). For example, if you're running late and walking quickly to catch the bus you're using the oxidative energy system. But if the bus pulls up and you need to sprint to catch it, the other systems become important because the oxidative energy system isn't able to supply energy fast enough to sustain this high-intensity effort.

Modified Borg Rate of Perceived Exertion Scale
Image from ACE

Fat Burning Zone and Exercise Intensity-

So, back to the fat burning zone... The wisdom behind this zone is that if you're exercising in a target heart rate range (read more about this here) of between 50-60% of your maximum heart rate (MHR) (4), or a level 3-4 on the on the modified Borg Rate of Perceived Exertion (RPE) Scale shown at left, (more about that here) you will be utilizing more of the oxidative system, which draws more energy from the body's fat stores.  While this is true, it's just part of the picture.

 Let's look at an example taken from research done at the University of Wisconsin at LaCrosse.  "A 160 pound male walks at a pace of 3.5 miles per hour. At this pace 40% of his energy is supplied from fat sources and 60% from carbohydrate sources.  On another day the same subject runs for 30 minutes at a pace of 6.5 miles per hour.  At this faster pace (higher intensity exercise), 25% of his energy is supplied from fat sources and 75% from carbohydrate sources" (7). Clearly, this would seem to validate the theory that lower intensity exercise utilizes a greater percentage of fat for energy.

However... Please hang in there for a little math, because this will distinctly illustrate the key point I'm attempting to make. "At the 3.5 miles per hour pace the subject burned a total of 240 calories during his 30 minute walk. He therefore burned 96 total fat calories (40% of 240 calories = 96 calories). At the 6.5 miles per hour pace, the same subject burned a total of 450 calories during his 30 minute run. Therefore, he burned 112 total fat calories (25% of 450 calories = 112 calories), which exceeds the number of fat calories burned during the lower intensity exercise session" (7). Not only did this study subject ultimately burn more fat calories, but he was able to burn more total calories overall working out at the higher intensity level for the same amount of time.

The bottom line-

Remember the energy balance equation? Calories in = calories out. When it comes to changes in body composition and weight loss, clearly higher intensity exercise is a better zone to shoot for because it burns more calories than the lower intensity so-called "fat burning zone". That being said, it is important to keep in mind your level of fitness. Obviously, if you're just beginning an exercise program you want to start at a lower intensity and build up gradually. This is where the progression and overload we talked about earlier comes into practice.  With all this talk about burning calories, let's not forget the impact that a healthy nutrition plan has on the "calories in" part of the energy balance equation. Armed with these fitness tools and knowledge, you're closer to achieving your weight loss goals and better health. 


Sources
(1) Whitney, E., Rolfes, S., Understanding Nutrition 11th ed., Thomson Wadsworth
(2) http://en.wikipedia.org/wiki/Metabolism
(3) Fahey, T., Insel, P., Roth, W., Fit & Well: Core Concepts in Physical Fitness and Wellness, 6th ed.
(4) IDEA Fit - http://www.ideafit.com/fitness-library/comparing-intensity-monitoring-methods-0
(5) American Council on Exercise (ACE) -http://www.acefitness.org/
(6) American Heart Association on body composition -http://www.americanheart.org/presenter.jhtml?identifier=4489
(7) Wescott, W.,  What is Fat Burning Zone?
(8) Hoeger, W. K., Hoeger, S. A., Lifetime Physical Fitness and Wellness: A Personalized Program 

Health, weight and the energy/nutrient density of foods

Have you ever thought of food as medicine?  Well, if you have you're in esteemed company, because Hippocrates had the same thought when he said, "Let your food be your medicine and your medicine be your food." In our so-called modern age, how have we managed to stray so far from this ancient wisdom?  It's a well-established fact that what we eat impacts our health. Yet, for many of us who have access to an abundant variety of foods, often times what we select are foods like a fast food burger and soft drink, that have a higher energy density, but are more nutrient poor (USDA).

World Cancer Research Fund

When it comes to making decisions about what to eat, it's helpful to understand the energy and nutrient densities of foods. You're probably familiar with calories. A calorie is a unit of measuring energy. When referring to food the term kilocalorie is used. A kilocalorie (or kcal) "approximates the energy needed to increase the temperature of 1 kilogram of water by 1 °C" (Wikipedia).  This is important to understand because the nutrient and energy density of foods relates to calories. In general:

• Nutrient dense foods provide more nutrients with fewer calories per unit volume than other foods in the same food group (USDA). Another way to look at it is the ratio of nutrients to calories (energy) a food contains.  
• Energy dense foods  provide more energy with more calories for their volume than nutrient dense foods. At first impression, more energy dense foods may sound healthier, but typically the reverse is the case. Energy dense foods often contain "empty calories" that come from fat and refined sugars making them a less healthy choice (Clemson.edu). Foods that are lower in energy density provide fewer calories per gram than foods with a higher energy density (CDC). 

For example, foods such as candies, desserts and processed foods, are high in energy density and calories, but they are not very nutrient dense. Whereas, foods like fruits and vegetables contain fewer calories for their volume, so they are lower in energy density, but are higher in nutrient density. This is important to note, especially when it comes to weight loss, because for the same amount of calories a person can consume a larger portion of a lower energy dense food (like an apple) and feel fuller for longer than they would if they ate a higher energy dense food (like a doughnut) (CDC). Plus, they would be getting much greater nutritional value from the apple than the doughnut. It's a win/win situation.

When grocery shopping the nutrition label found on prepackaged foods can be helpful in determining its energy content per 100 grams. The World Cancer Research Fund has a useful food energy density calculator here, but as a general rule:

• high energy density (fast food, chips, cakes, cookies, butter and margarine) fall in the 225-275 kcal/100g range
• medium energy density (bread, lean meat, poultry, fish) fall in the 100-225 kcal/100g range
• low energy density foods (cooked grains like brown rice, whole meal pasta, beans and lentils) fall in the 60-150 kcal/100g range
• lower energy density foods (most fruits and vegetables) fall in the 10-100 kcal/100g range

How does the composition of food affect energy density? Three factors play an important role in the energy density of food:

• Water - Adds volume/weight to food, but not calories because water contains 0 kcal/gram. Fruits and vegetables contain a lot of water. For example, grapefruit "is about 90 percent water and has just 38 calories in a half-fruit serving. Carrots are about 88 percent water and have only 52 calories in 1 cup" (Mayo Clinic).
• Fiber - Adds volume and 1.5-2.5 kcal/gram to food, but fiber also increases the time it takes to digest foods and this contributes to our feeling fuller for a longer period of time after eating fiber rich foods.
• Fat - On the other side of the energy density spectrum is fat, which contains 9 kcal/gram.  Fat increases the energy (calorie) density of foods. For example, "one teaspoon of butter contains almost the same number of calories as 2 cups of raw broccoli." (CDC).

Keeping these factors in mind, it's not too difficult to spot a high energy density food.  They are usually high in sugar and fat, low in fiber and water and processed.

Weight loss/maintenance and energy density of foods - Research has shown that eating a diet that is "rich in low energy dense foods like fruits, vegetables, whole grains, lean meats and low fat dairy products helps people lower their caloric intake" (CDC).  However, even though calories consumed are usually lower with this type of eating, typically eating a diet that contains low energy foods doesn't mean skimping on nutrients. On the contrary, veggies and fruits are the superstars on our plates and will provide us with a good heaping of the required daily allowance of nutrients (CDC).

Not only can there be a weight loss/maintenance benefit from eating lower energy dense foods, but there is also strong evidence to suggest a reduction in the risk of certain cancers. In 2007, the UK's World Cancer Research Fund (WCRF) published findings from a panel of 21 of the world's top health experts who reviewed the current scientific research. After 6 years of work they produced the Expert Report. It is the most comprehensive statement "on the links between lifestyle and cancer risk. Because of the thoroughness of the Report and the expertise of the panel, people can be confident that it is the best advice on how to reduce cancer risk that is available anywhere in the world." (WCRF). Although it's been suggested for some time, the science is proving that taking steps toward improving nutrition, increasing physical activity and just generally making a healthy lifestyle a priority will actually help reduce risk for a recurrence of cancer, among other things.

In an effort to increase awareness of the health benefits of eating more fruits and vegetables, the CDC has designated September as National Fruits and Veggies More Matters Month. (Their site provides some useful information, along with a fruits and veggie consumption calculator.) So, it seems appropriate that step one of creating a diet that is low in energy density has to do with, you guessed it, fruits and veggies! 

First step to take to create a diet low in energy density:

Incorporate a larger portion of fruits and veggies into meals.  For many people, purchasing fruits and vegetables can be limited by their cost. The CDC has a helpful resource entitled 30 Ways in 30 Days to Stretch Your Fruits and Veggies Budget. You can find it here. Eating more fruits and veggies is the first step in reducing our diet's energy density because they contain more water and fiber and less fat than other foods.

However, not all fruits and veggies are created equal. The CDC suggests incorporating more cruciferous vegetables.  These include "broccoli, Brussels sprouts, cabbage, cauliflower, collard greens, kale, kohlrabi, mustard, rutabaga, turnips, bok choy, and Chinese cabbage. Arugula, horse radish, radish, wasabi, and watercress are also cruciferous vegetables" (Linus Pauling Institute). Then rounding out meals "by adding starchy fruits and vegetables, legumes, lean meats and low-fat dairy food.  These foods are important for creating a healthy, balanced diet" (CDC).

The next post will discuss the other steps as well as a few helpful strategies that will aid in creating a diet that is low in energy density and high in nutrient density.  Even though the term "diet" is used, this way of eating is a lifestyle.  The TLC way to weight loss discusses in more detail here the importance of adopting healthy habits, rather than attempting various diets.  Also, dieting is usually associated with calorie counting and hunger.  This isn't the case with eating more low energy/high nutrient density foods. With all the mounting scientific evidence that underscores the importance of healthy nutrition, it seems more critical than ever to get back to thinking about our food as medicine.



Sources
National Institutes of Health
http://www.jacn.org/cgi/content/abstract/23/2/163http://www.ajcn.org/cgi/reprint/72/4/929.pdf
http://www.wcrf-uk.org/PDFs/EnergyDensity.pdf
http://medical-dictionary.thefreedictionary.com/caloric
http://www.mypyramid.gov/steps/nutrientdensefoods.html
http://www.clemson.edu/extension/hgic/food/nutrition/nutrition/dietary_guide/hgic4062.html
http://lpi.oregonstate.edu/infocenter/foods/cruciferous/

Understanding the omegas

Are you finding it challenging to understand precisely what it is you’re supposed to eat and why it’s good for you? Unfortunately, part of the difficulty in making determinations about our food can result from misinformation we may receive about nutrition. Compounding the problem of a better understanding of healthy nutrition are the intricacies of the subject matter itself.

At first glance, nutrition seemed fairly straightforward to me. In the world of fitness training, it can be as simple as: calories in equal calories out for weight maintenance.  That understanding is definitely important, but there’s a whole lot more going on between the calories in and the calories out. You might find, as I have, that an awareness of the finer details aids in a better understanding of the bigger picture. So, in order to make more educated choices about eating for our health, I've found it helpful to take a closer look at the foods I eat and how they affect me. This educational journey through fat nutrients was a veritable alphabet soup of acronyms and a few of the concepts required some critical thinking. Yet, in the end I found it was worth it. However, if you're less interested in the fascinating workings of fatty acids, just skip down to the bottom line section of the post.

Well, it's good to know that I'm not alone in my quest for nutritional knowledge. Let's journey on and get back to the topic of discussion in the last 2 posts: fats and specifically the polyunsaturated fatty acids (PUFA’s) known as omega-3 and 6.

Omega-3 and 6: Why are they important?
In case you missed the previous posts on fats, omega-3 and 6 are also known as essential fatty acids (EFA’s).  This is because our bodies can’t make enough of them, so they must come from the foods we eat. EFA’s are extremely important in, among other things, cell membrane structure and function, cardiovascular health, vision, the regulation of gene expression and the proper working of our nervous system (Linus Pauling Institute).

Omega-3 and 6: What are they?
Omega-3 and omega-6 are terms which actually represent 2 families of fatty acids.  In the omega-3 family the nutritionally important fatty acids include: alpha-linolenic acid (ALA), eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). EPA and DHA can be made from ALA. However, the body doesn’t do this very efficiently (around 5% in men and slightly higher in women) (Wikipedia). The body can also convert EPA into hormone like substances called eicosanoids. Omega-3 eicosanoids are thought of as being less prone to cause inflammation. Unfortunately, since the body doesn’t convert EPA very efficiently, the rate at which these omega-3 eicosanoids are produced is much slower than that of omega-6.

In the omega-6 family there is linoleic acid (LA), gama-linoleic acid (GLA) and arachidonic acid (AA). Through a cascade of chemical reactions the body can make AA from LA. However, because of the excess of LA compared to ALA in the Western diet, the result is usually a greater formation of AA than that of the EPA that is made from omega-3. The body also converts AA into eicosanoids and because of the greater amounts of available AA more of the omega-6 eicosanoids are formed as a result.

The eicosanoids formed from the omega-6 AA are thought to be more "pro inflammatory" than the eicosanoids converted from ALA (AHRQ Evidence Report). If you're looking for more information on inflammation, this topic is discussed in another post.  The important point here is that anything that promotes an inflammatory state in the body for long periods of time isn't good (Linus Pauling Institute).

Now we’re getting to the heart of the matter.  Some experts believe that the current Western diet contains as much as anywhere from 10-25 times more omega-6 than omega-3. Compounding the situation is that omega-3 and omega-6 eicosinoids compete to use the same chemicals in order to be transformed. So the ratio of omega-3:omega-6 directly affects the type of eicosanoids formed and our Western diet encourages more production of omega-6. Remember that eicosanoids produced from the AA derived from omega-6 are considered to be pro-inflammatory.

Omega-3 and 6: Are their ratios important?
If you’ve been following the previous posts in this blog you know that studies have shown that there are definitely health benefits associated with including more omega-3’s in our diet. Table 2 below shows some of the benefits of omega-3's DHA and EPA (Lavie, et al).

Research suggests that an imbalance between omega-3 and omega-6 is an underlying cause in many diseases, including cardiovascular disease, cancer, and inflammatory and autoimmune diseases (Simopoulos, A.P.). It's thought that omega-3 eicosanoids have regulating effect over omega-6 eicosanoids.  When the two are totally out of balance, this regulating effect is removed and the eicosanoids from omega-6 exert a more "pro-inflammatory" state. It seems experts aren't in agreement yet on a specific ratio of omegas, however they do seem to recognize that more eicosanoids from omega-6 than from omega-3 contributes to inflammation, blood vessel constriction (which causes increases in blood pressure) and blood clotting (Linus Pauling). 

Omega-3 and 6: How much to eat and from what foods?
So, aside from the ratios, how much of each omega is necessary for optimal health and what foods do we eat to get them? Well, as far as I can tell, at this point in time the US hasn’t assigned a Recommended Daily Allowance (RDA) for omegas.  However, the Food and Nutrition Board of the U.S. Institute of Medicine has established adequate intake (AI) levels for both omega-6 and omega-3 fatty acids. You can view the AI’s here at the Linus Pauling Institute. An example  of the AI's for adult males 19-50 years old is 17 grams per day and for females it's 12 grams per day. For males 51 years and older the AI for LA decreases to 14 grams per day and 11 grams per day for females.  The Linus Pauling Institute also has a list of the best food sources for omega-3 and 6 and you can check that out here.

Image from www.extension.org

There has been some research on omega supplementation in the case of individuals with cardiovascular disease. The American Heart Association recommends a combined EPA and DHA intake of approximately 1,000 mg/day for people with this disease. However, for people who don’t have cardiovascular disease their suggested RDA is based on fish consumption. They advise eating two oily fish meals per week. This amount of fish would provide about 400-500 mg/day of EPA + DHA (Linus Pauling Institute). Remember to be careful to avoid fish containing higher levels of mercury and other contaminants.

According to a report on EFA's by the Agency for Healthcare Research and Quality Evidence, Acceptable Macronutrient Distribution Ranges (AMDR’s) have been established for the essential fatty acids. You can view their table of sources and proportions of omega-3 foods and supplements here. 

Bottom Line
As you can see from the above information, knowing how much and what ratio of omegas to consume is a rather confusing and complicated subject. When it comes to the question of what to eat, I like how simply the Harvard School of Public Health puts it: “out with the bad and in with the good.”  Here are their suggestions for how to eat better and also get more of the healthy fats:

•  Try to eliminate trans fats from partially hydrogenated oils. Check food labels for trans fats; avoid fried fast foods.
•  Limit your intake of saturated fats by cutting back on red meat and full-fat dairy foods. Try replacing red meat with beans, nuts, poultry, and fish whenever possible, and switching from whole milk and other full-fat dairy foods to lower fat versions.
• In place of butter, use liquid vegetable oils rich in polyunsaturated and monounsaturated fats in cooking and at the table.
•  Eat one or more good sources of omega-3 fats every day—fish, walnuts, canola or soybean oil, ground flax seeds or flaxseed oil.

So, I’m no longer stuck in the old thinking that generic, low-fat eating is the way to go. From now on when it comes to fats it’s out with the bad and in with the good. Making educated choices about the foods we eat may seem complex at first, but with practice it becomes easier. Don't you think it's worth the effort to understand which food is healthier than another? When you consider how profoundly what we put into our bodies affects our health, we really owe it to ourselves and those we love to practice healthy nutrition habits! 

Sources
Simopoulos, A.P., Evolutionary aspects of diet, the omega-6/omega-3 ratio and genetic variation: nutritional implications for chronic diseases. Retrieved from  http://www.ncbi.nlm.nih.gov/pubmed/17045449
Carl J. Lavie, MD, Richard V. Milani, MD, Mandeep R. Mehra, MD and Hector O. Ventura, MD, Omega-3 Polyunsaturated Fatty Acids and Cardiovascular Diseases,  J Am Coll Cardiol, 2009; 54:585-594, doi:10.1016/j.jacc.2009.02.084, Retrieved from http://www.natap.org/2009/HIV/080509_04.htm
Linus Pauling Institute: http://lpi.oregonstate.edu/infocenter/othernuts/omega3fa/#intro
http://www.hsph.harvard.edu/nutritionsource/what-should-you-eat/fats-full-story/index.html
http://www.ncbi.nlm.nih.gov/bookshelf/br.fcgi?book=erta89&part=A131672#A131673
Edwards,T., Inflammation, pain, and chronic disease: an integrative approach to treatment and prevention.Retrieved fromhttp://www.ncbi.nlm.nih.gov/pubmed/16320856