Metabolic Fuel

In the article that I referenced last night (regarding the erroneous contention that 3500 cals was the equivalent of one pound of body weight), there was a separate discussion regarding the macronutrient composition of diets. 

What?

When I say macronutrient, you should hear; fat, protein and carbs.  For as long as I have been writing about and studying obesity (ten years now), people have asked and studies have explored, which is better – low fat, low carb or  high protein diets.  My answer has been and the research supports, a calorie is a calorie.  For this truism, Dr. K. Hall and the other authors (from the study referenced in the last post) do not object.

The sub article does give three possible reasons why the composition of the diet might impact the amount of weight lost.  By this I mean, if a person consumes 70% carbs and 15% protein and fat – or any such combination, does it change the amount or the speed in which they will lose weight.

In the short term, which is all that has really been studied, there is no true difference between types.  In the end, if a person consumes less calories than they have been and everything else stays the same, they will lose weight.  This is often true of exercise as well.  IF one adds more activity to their day (consistently) and does not change anything else, they will lose weight (albeit at a slower pace).  What tends to happen with the addition of PA is that people DO eat more.   

Okay – the three points that were made in the article.

Intracellular or physiological changes take place within the body based on the amount of each macronutrient that a person consumes.  I learned today that the fat, protein and carbohydrates that we take in are mirrored in the body by what is called metabolic fuel.  In the body, it is fat, protein and glycogen.  The body maintains a balance of the metabolic fuel.  It has been shown in lab experiments that if you change your balance, say you eat more carbs and your body needs some fat, it  will then use the stored fat to make up the difference.   This is possible, but the effect to date has not been enough to unseat the calorie is a calorie stance.

Energy burn can be impacted by the foods that we eat.  Certain macronutrients have an immediate but short term effect on your metabolism in the few hours after you eat it.  Scientists are using simulation techniques to explore this phenomenon, but again, it has not been found to improve outcomes – or cause more weight loss then simply creating a negative energy balance.  (less in and more out)

The composition of a meal may have an impact on one’s satiety and reduce hunger so that over consumption (over eating) does not occur.  When discussing this area, the article author’s noted how notoriously bad “free living” folks were at reporting what they actually eat and in following the recommendations of any meal plan.  

So for us the bottom line is – a calorie is a calorie.  Now as I have said before, this is regarding weight.  For health – what you eat – i.e. what the DGA 2010 recommends – is of great consequence and importance. 

Don’t eat all your calories in chips, dip and twinkies.