Saturday, September 29, 2012

Is a Calorie a Calorie?

I came upon an interesting article "Is a Calorie a Calorie?" written by Malden Nesheim and Marion Nestle today. I agree with everything they say except their conclusion. To me, a calorie is not a calorie if the source of the calorie differs. A calorie from plant-based whole food might be less or more than a calorie as compared to a calorie from processed food.


Plant based whole foods (whole grains, fruits, nuts, legumes and vegetables) all contain cellulose, a structural component of the primary cell wall, often referred to as dietary fiber. The energy (carbohydrate, fat and protein) is contained inside the cell wall. Cooking breaks down most cell walls and releases the energy we consume. We also digest cellulose with the aid of gut microflora, and the extent of digestion varies from one individual to the next (here). The energy produced are shared between us and our gut flora and not counted as Calorie. Most of the cellulose, or dietary fiber, acts as a hydrophilic bulking agent for feces. In other words, most cellulose is not digested, therefore, not counted as Calorie.

On the other hand, as argued in the above mentioned article, "But certain foods, again, retain some of their calories as they pass through our gut. For example, the fat in almonds and certain other nuts is incompletely digested. In a 2012 study, USDA scientist Janet Novotny and her colleagues found that the measured energy content of a 28-gram serving of almonds was actually 32 percent less than the Atwater values estimate." Is it because of the cellulose in almonds that makes it difficult for us to get all the energy content or is it because it costs a lot of energy to digest almonds? I do not know. I agree with the above author and a calorie is a calorie if you compare low carb diet to low fat diet and strictly in relation to weight gain or loss. But I do believe there is a huge difference between 1000 Calorie from refined pure starch and 1000 Calorie from mixed portion of whole grains, fruits and vegetables. We are still comparing carbohydrates to carbohydrates. If you want to compare fat, 1000 Calorie from pure fat/ oil is very different from 1000 Calorie taken from nuts. Whole foods are harder to digest, therefore, either we lose some Calorie because we could not get at them or because it costs more energy to digest them. In addition, whole foods contain vitamins/ minerals/ phytochemicals and fiber etc. that are beneficial to our health.


Obesity in itself is not a disease. As a matter of fact, about25% of obese people are healthy. Eating less is good, but eating well is better. Since we have to teach people how to eat healthy, we might as well teach the whole shebang.

Telling people including myself to eat less never works. We have such abundance of food available to us and a good appetite is healthy. It is only human to want to eat. But we can slowly trick ourselves into eating habits in a way that even though we are eating a large volume, we actually do not consume excessive Calorie. So in our house, we eat vegetable soups often. We snack on raw fruits and nuts. We never consume sugary drinks (including fruit juices). I personally believe there is nothing healthy about processed fruit juices. Once you get used to eating healthy, your body no longer craves for junk food.

No comments:

Post a Comment