Research Questions Whether All Calories are Equal

The standing idea about caloric intake is that a calorie is a calorie and it doesn’t matter what we eat in terms of losing weight, gaining weight or maintaining weight.  A calorie is the amount of energy that is expended when the body metabolizes whatever food we’ve eaten.  If a calorie were thought of in terms of electricity, it would be like saying that the calories from different food sources are exactly the same as the wattage from different power sources, and that’s exactly what the theory is: that we could survive eating nothing but apples for the rest of our lives without any effects at all in terms of weight loss, gain or maintenance.  However, a new study may have blown that theory completely out of the water.

The study, headed by David S. Ludwig, M.D., Ph.D., found that all calories may not actually be equal in terms of how the body processes them.  While it is not yet clear exactly what the differences are, it is quite clear that some diets are potentially better than others for weight loss.  Participants in the study were asked to follow three different diets as strictly as possible for a set period of time each.  During that time, researchers would measure the amount of calories each subject burned with very sensitive equipment to ensure the most accuracy possible when taking measurements.

Each subject was to eat no more than 1600 calories each day.  The first phase had the subjects following an ultra-low-fat diet, the second had them following a low-glycemic diet, and the third had them following a low-carb diet.  What may be surprising to those that were holding onto the view that all calories are created equally, and what is not surprising to those who were convinced that they were not but had zero evidence to the contrary, is that it seems our bodies do care what kind of fuel we’re giving it.  This really shouldn’t have been that surprising.

For years, it has been suggested that we cut back on refined sugars.  Why?  Well, it helps contribute to Type 2 diabetes, doesn’t it?  Don’t eat a lot of saturated fats, we’re told.  Why?  Well, the heart doesn’t care for it all that much.  Don’t cook your red meat to well-done every time!  Well, why not?  It’s safer, isn’t it?  Oh, HCA is formed when meat is cooked for longer periods and I could wind up with malignant tumors?  Good to know!  So, why is it even remotely surprising that different foods might have an effect on how our bodies use calories from different food sources and how they deal with calorie expenditure?

The study showed that those on the low-carb plan burned around 300 calories more each day than those on the low-fat diet, and those on the low-glycemic plan burned around 150 calories more each day than those on the low-fat diet.  It has already been suggested that low-fat and ultra-low-fat diets may have an effect on metabolism, but it hasn’t been until this study that there has been any concrete evidence toward that idea.  Low carbohydrate plans do come along with a few caveats, the main one being that they may cause issues with the kidneys and liver.  Low-glycemic diets, however, provide a great calorie burning boost without the harmful side effects.

It certainly seems that a calorie most certainly is not a calorie after all.  More studies will have to be done to determine just what type of role certain foods play in terms of metabolic reactions in the body, fat loss and weight management, but it’s promising that science has gotten this much closer to helping us with a better understanding.