June 3, 2011

Carbohydrate, Protein and Fat: Is the Question Quantity or Quality?

green plateOn June 2, 2011 the food pyramid was put to rest and the simple, straightforward plate was introduced as the new icon for healthy eating. While I'm pleased with this new colorful, simplified food icon, I by no means think it will put a halt to nutrition debates, including these two questions:

  • What percent of calories from carbohydrate, protein and/or fat should we eat?
  • Is it healthier or better for managing blood glucose or fat levels to eat more or less: carbohydrate, protein or fat?

These questions, in my humble opinion, have and continue to receive too many research dollars and too much media (and thus, consumer) attention.

Please hear me out...

We seem fixated on the quantity questions regarding our, so-called macronutrients – our main sources of calories (that’s carbohydrate, protein and fat). Yet the research to date as well as the recommendations from respected bodies, such as Institute of Medicine and the Dietary Guidelines for Americans Advisory Committee Report, proves out a few stark realities. I’ll delve into these here and detail why our focus should be squarely on the quality of carbohydrate, protein and fat we eat, not the quantity.

Reality #1: American adults have been and continue to divide our calories from this approximate division of carbohydrate, protein and fat (yes, alcohol contributes calories, but it’s a minor contribution for most):

Macronutrient Percent of Calories
Carbohydrate45 – 52
Fat  34

Ref: DHHS/USDA Dietary Guidelines for Americans, www.healthierus.gov/dietaryguidelines

Reality #2: Americans are being encouraged (via the Dietary Guidelines for Americans and the recently unveiled ChooseMyPlate.gov) to consume our calories from this approximate division of carbohydrate, protein and fat:

Macronutrient Percent of Calories
Carbohydrate45 – 65
Protein10 - 35
Fat 20 - 35

Ref: Institute of Medicine: Dietary reference intakes: Energy, carbohydrate, fiber, fat, fatty acids, cholesterol, protein and amino acids. Washington, DC, National Academies Press, 2002.

These percentage of calories – amounts we eat vs. amounts we’re encouraged to eat, are pretty darn close, aren’t they?

Then what’s the fuss?

Reality #3:
Our nutrition problems arise when we dig deeper to inspect the array of food sources from which we derive our carbohydrate, protein and fat. Let’s take our sources of carbohydrate as an example:

Food/Nutrient Amount Eaten – U.S. Adult What’s Recommended
Carbohydrate 45 – 52% (of calories) 45 – 65%
Dietary Fiberat best ½ of needed 25-35 grams/day
Whole grains eking out 1 serving/day  3 servings/day
Fruit 1 cup/day 2 cups/day
Vegetables 1 cup/day 2 1/2 cups/day
Dairy foods 1.4 cups/day 2 – 3 cups/day
Added sugars 22 tsp/day (AHA ref) ~6 tsp women, 9 tsp men (AHA ref)

Refs: DHHS/USDA Dietary Guidelines for Americans,healthierus.gov/dietaryguidelines, Dietary sugars intake and cardiovascular health. A  Scientific Statement from AHA. Circulation, 2009. 

When you glance at the chart about our sources of carbohydrate it becomes vividly clear that we don't eat too much carbohydrate. In fact we’re on the low side of the 45 to 65 percent of calorie recommendation noted above. Our problem? The quality of our food sources of carbohydrate are out of wack. Way too much added sugars (think sugars sweetened soda - yes they lead the pack!), pastries and desserts made from refined grains, and fruit drinks) and clearly not enough, fruits, vegetables, whole grains, and low fat dairy foods. Yes, the foods we’re being encouraged to eat more of and the ones which derive most of their calories from carbohydrate.

Now to fat as another example. We eat a few more of our total calories from fat than is desirable for health, but our intake is just at the top end of the recommended amount. When we again dig deeper, we discover that a larger amount our calories from fat are contributed by saturated fat, and we don't eat enough of the healthier fats: mono and polyunsaturated fats (omega-6 and 3’s).

On to action steps:
A critical point - foods are packages of nutrients. They contain a mix of nutrients. For example, a piece of whole grain bread contains mainly carbohydrate and a bit of protein. A piece of cheese contains protein and a good bit of fat.

Another important point. If you choose to eat less protein you’ll reflexively eat less fat and more carbohydrate, just by virtue of your food choices. Sources of protein generally contain some fat – think meat, cheese, seafood, eggs, nuts. Sources of carbohydrate can contain no protein and fat - think fruit, or carbohydrate and a bit of protein – think breads, cereals, whole grains. Sources of carbohydrate tend to contain no or minimal fat (that is before you prepare them for eating).  

An interesting research finding is that people can be asked to change the amount of the carbohydrate, protein and fat they eat, but they find this very hard to accomplish. A weight loss study called POUNDS LOST showed this. People were asked to follow one of four diets with varied and distinct amounts of carbohydrate, protein and fat. At the end of this two year study, the researchers found that people never achieved the goals of the diet they were to follow. Plus they gradually gravitated back to the distribution of the nutrients they were used to and comfortable with. Yes, our eating habits are deep rooted!

To the bottom line:
Let’s stop focusing so much energy, words and resources on how much carbohydrate, protein and fat to eat. Instead, let’s focus our attention squarely on the quality of our nutrients. Choose healthy foods that contain minimal calories and maximal nutrition - plenty of vitamins, minerals and dietary fibers.

And let’s respect the fact that people have varied eating styles, all of which can be within the realm of healthy eating if foods with quality nutrients occupy your plates. If you are a vegetarian and are inclined to eat a greater percent of your calories as carbohydrate, then do so. Up to 65% of your calories as carbohydrate is within the recommended window.  If your food preferences naturally lean towards meats, then work to choose lean sources, prepare them healthfully and eat them in reasonable portions.

Don’t try to make wholesale changes in the way you eat. Find your comfort zone. And pay utmost attention to the quality of the foods you eat.