Archive | April, 2013

Thermodynamics: a Calorie is NOT a Calorie

4 Apr

Thermodynamics: a Calorie is NOT a Calorie

by Tim Skwiat, MEd, CSCS, Pn1

While I would certainly agree that energy balance plays a predominant role in weight loss and weight gain,  I do not agree that the quality of one’s food choices does not make a difference. A calorie-based approach to weight loss — strictly referring to the quantity of calories and not the quality — is not the most effective or efficient way to reach your weight loss goals.

While I could offer an off-the-wall example of consuming 2,000 calories a day from pure sugar versus the same number of calories from carrots, that is not applicable real world. However, there is strong data to suggest that simply replacing calories from carbohydrates with an equivalent amount of protein is enough of a stimulus to promote improved body composition.

As a matter of fact, researchers at the University of Illinois assigned women to either a high-carbohydrate diet or a high-protein diet, both with the same overall calorie intake. After 10 weeks, both groups lost weight while dieting, but the high-protein group — which simply replaced some calories from carbohydrate with protein — lost more weight overall and nearly double the amount of body fat.

Not only does a higher protein intake yield greater weight loss, more importantly, it results in more fat loss and retention of more calorie-burning lean muscle mass. What’s more, the high protein group had improved levels of blood triglycerides and reported greater satiety throughout the course of the 10 weeks of dieting. The scientists concluded with the following:

“This study demonstrates that increasing the proportion of protein to carbohydrate in the diet of adult women has positive effects on body composition, blood lipids, glucose homeostasis and satiety during weight loss.”

While empirical evidence suggests that rising obesity rates parallel the increase in consumption of processed foods, another group of researchers from the Ponoma College Department of Biology set out to see if there was a difference in the thermogenic response to eating whole foods versus processed foods.

These researchers found that both the Resting Metabolic Rate (RMR) — the primary contributor to your metabolism — and the TEF of eating whole foods is significantly higher than eating the same number of calories from processed foods. The TEF of the whole food meal was nearly double that of the processed food meal, which was comparable to the processed food meal in overall energy, proteins, carbohydrates, and fats.

Participants burned 50% more calories after eating the whole food meal. What’s more, the participants that consumed the processed foods experienced a drop in their metabolic rate below their RMR in the hours after the meal, while the whole food group never fell below their RMR. The whole food group also experienced an elevation in metabolism an hour longer after the meal than the processed food group.

If that’s not enough convincing information, a recent study at the University of North Carolina at Chapel Hill has shown that regular consumption of processed junk foods — implicated in all manner of health problem — is the biggest dietary driver of tissue inflammation. The study, recently published in the PLOS ONE online journal, analyzed inflammatory responses in rats fed different diets: control diets, a lard-based high-fat diet and a “cafeteria junk-food” diet consisting of nutrient-poor snacks such as salami, chocolate, cookies and chips.

Lead researcher Liza Makowski stated, “The rodents that ate the junk-food diet gained the most weight and displayed tissue inflammation.” The scientists were particularly interested to find a specific metabolite in the junk-food eaters that could spur as much inflammation as toxins in certain bacteria. “This metabolite could be the signal that starts the snowball effect of inflammation leading to metabolic syndrome,” Makowski says. This can result in obesity and high blood pressure, and is a precursor to type 2 diabetes, cardiovascular disease and cancer.

While the research correlating food additives — from artificial sweeteners to dyes to preservatives — is in its infancy, researchers are investigating this connection every day to help point a finger to a causative relationship.

One very common food additive with which many of us are familiar, MSG, has already been linked to obesity in research. Researchers that collected data from the China Health and Nutrition Survey concluded, “MSG consumption was positively, longitudinally associated with overweight development among apparently healthy Chinese adults.”

Researchers have also made connections between artificial sweeteners and weight gain. In one study that recently appeared in the scientific journal Appetite, scientists compared the effects of feeding rats yogurt sweetened with either sucrose (i.e., table sugar) or the artificial sweeteners saccharin (Sweet ‘n Low®) and aspartame (Equal®) on body weight and total caloric intake. The researchers found that, compared to sucrose, the addition of the artificial sweeteners to yogurt resulted in increased weight gain, despite similar total caloric intake among groups.

Do you still believe that a calorie is a calorie, or that weight loss is simply a matter of pure thermodynamics? Put these take-home points to use right away to optimize your metabolism, overall health, and weight loss efforts:

  • Increase your protein intake and reduce your overall carbohydrate intake.
  • Focus predominantly on whole foods, or what we call one-ingredient foods.
  • Reduce or completely eliminate processed foods.
  • Reduce or completely eliminate foods with additives, like artificial sweeteners and preservatives.


Layman DK, et al. A reduced ratio of dietary carbohydrate to protein improves body composition and blood lipid profiles during weight loss in adult women. J Nutr. 2003 Feb;133(2):411-7.

Barr, S., Wright, J. Postprandial Energy Expenditure in Whole-Food and Processed-Food Meals: Implications for Daily Energy Expenditure. Food and Nutrition Research. July 2010. 2(54), 144-150.

Sampey BP, et al. Metabolomic profiling reveals mitochondrial-derived lipid biomarkers that drive obesity-associated inflammation. PLoS One. 2012;7(6):e38812.

He K, et al. Consumption of monosodium glutamate in relation to incidence of overweight in Chinese adults: China Health and Nutrition Survey (CHNS). Am J Clin Nutr. 2011 Jun;93(6):1328-36.

Feijó Fde M, et al. Saccharin and aspartame, compared with sucrose, induce greater weight gain in adult Wistar rats, at similar total caloric intake levels. Appetite. 2013 Jan;60(1):203-7.