Written by: Kevin Cann
Recently there was an important research project published in the Journal of American Medical Association (JAMA). Researchers are trying to understand the mechanisms behind the obesity epidemic that is seen in this country. One area that we fail to grasp a solid understanding of is why people will lose weight and over time put that weight back on. In some cases they will even gain more weight then they lost.
For the longest time we have been led to believe that our inability to count calories, and exercise, is why we continue to get more obese as a nation. In a study published in the American Journal of Medicine in 1997 it concluded by saying “Reduced fat and calorie intake and frequent use of low-calorie food products have been associated with a paradoxical increase in the prevalence of obesity” (Heini, 1997). This study goes on to state that it believes it is the lack of physical activity causing us to become obese. Is it really the lack of physical activity?
According to the CDC’s stats for physical activity 46.9% of the American population met the standards for aerobic exercise. If almost half of us are at least going for a run every once in a while and we are eating fewer calories as a country, why do we continue to get more obese and more sick?
This current study in JAMA does not answer the questions, but is a step in the right direction to understanding the mechanisms associated with obesity. This study was attempting to answer the question as to why people put on weight following a weight loss protocol. They attempted to answer this question by examining the effects of 3 diets differing in macronutrient consumption and glycemic load. The test subjects were 21 overweight and obese adolescents. This was a three-way controlled crossover study comparing a low-fat (60% carbohydrate diet), low-glycemic (40% carbohydrate diet), and a low-carbohydrate (10% carbohydrate diet). Carbohydrate sources were “healthy” sources such as whole grains, fruits, and vegetables.
To summarize the results: the low-carb diet had the greatest increase in HDL, the greatest decrease in triglycerides and PAI-1 (arthrogenic factor), showed the greatest insulin and leptin sensitivity, and at rest burned 300 calories/day more than the low-fat diet and 150 calories/day more than the low-glycemic diet. The low carb diet however showed the highest amounts of excreted cortisol, and also the highest levels of C-reactive protein (CRP). This, in the long term, may induce heart disease (Ludwig, 2012).
The media has interpreted this data to mean that the low-glycemic diet has almost the same amount of positives as the low carb diet, but without the risk of heart disease in the future. The data in this research does not say that. The CRP levels in the low-carb group were .87. In the American Heart Association’s journal Circulation, CRP levels of less than 1 correspond to a low risk of heart disease (Ridker, 2003). It is widely known that HDL may be preventative of heart disease, and high triglycerides are a risk factor for heart disease. If the low-carb diet increases HDL the most and lowers triglycerides the most while maintaining a low risk score on a CRP test, how would the risk for heart disease in the future be greater?
When looking at the cortisol excretion rates we need to keep in mind these patients were on a 10% carbohydrate diet. This is extremely low. According to Loren Cordain the paleo diet consists of roughly 20-40% carbohydrates. I would like to see these results recalculated with these patients on a diet of a few more carbohydrates and also removing the grains from the selected carbohydrate sources, but that was not the point of this study.
In the comments of the study, it was stated “This study challenges the notion that a calorie is a calorie” (Ludwig, 2012). This is the biggest take away in my opinion. This study shows that it is not as easy as counting calories and the mechanisms behind the obesity epidemic are much more complicated than most people think. In my opinion, the data in this study shows a low-carb diet to be more effective at decreasing the risk of heart disease, regulating appetite, and maintaining weight loss. Hopefully this research study kicks off other ones like it, and sometime in the near future we have hardcore scientific data supporting a proper treatment plan for the disease of obesity. Until then we still have strong anecdotal data that the paleo diet is the best treatment for obesity.
Nataradjan, Pareep (2010). High Density Lipoprotein and Coronary Heart Disease. Journal of American College of Cardiology. Retrieved on June 29, 2012.
Ridker, Paul (2003). Clinical Application of C-Reactive Protein for Cardiovascular Disease Detection and Prevention. Circulation. Retrieved June 28, 2012.
Heini, AF (1997). Divergent Trends in Obesity and Fat Intake Patterns: the American Paradox. UK Pubmed. Retrieved June 28, 2012.
Ludwig, David (2012). Effects of Dietary Composition of Energy Expenditure During Weight Loss Maintenance. JAMA. Retrieved June 27, 2012.
Kevin is owner of Genetic Potential Nutrition. He is a holistic nutritionist, wellness coach, and strength coach. He works with people fighting illness, to competitive athletes. Check out his site at www.geneticpotentialnutrition.