Definition of Obesity: “…the presence of excess body fat that threatens or affects health”
Although weight gain has long been looked at for decades as simply a caloric imbalance–more calories ingested compared to calories burned–for which the advice has been simply to eat less and exercise more, there is increasing evidence that not all calories are created equal, and that obesity as simply a function of “gluttony and sloth” may not be accurate or fair.
Although genetic factors do play a large role, heritability is not destiny.
Reduced energy intake is effective in weight reduction, but surprisingly, such diets generally do not work well in the long term:
- “Dietary therapy remains the cornerstone of [obesity] treatment and the reduction of energy intake continues to be the basis of successful weight reduction programs,”
observes The Handbook of Obesity, a textbook edited by George Bray, Claude Bouchard and W. P. T. James, three of the most respected names in obesity research, and first published in 1998. It then goes on to acknowledge that the results of such therapy “….are known to be poor….”
Regardless of body weight or weight loss, an increased amount of exercise increases health—you can be overweight and generally healthy.
Physical activity or exercise in sufficient dose aids in long term weight maintenance, but is not usually the primary driver of weight loss.
Although low fat diets have been used successfully for weight loss, they have been shown to be less effective than low carbohydrate diets in now 18 randomized control trials.
Eating more whole foods is optimal nutrition. Refined (processed) foods tend to be more concentrated in calories, usually are reduced in or devoid of fiber, water, and micronutrient content, cause quicker absorption of calories, more likely to cause spikes of blood sugar and serum insulin, a tendency to overeat, and a decreased effect on satiety. These foods also usually have undesirable additives, and the missing nutrients may actually drive you to eat more. Where possible eat foods without labels. And understand the glycemic index of foods, for the reasons stated below.
Most convenience foods are convenient, but they are often have a high glycemic index and they are not usually nutritious. They may be particularly unhealthy for those who are relatively carbohydrate intolerant. If your great grandmother wouldn’t have recognized it (as author Michael Pollan suggests in his book, In Defence of Food), it is probably not a real food!
Refined and starchy carbohydrates—foods containing easily accessible simple sugars—drive serum insulin levels higher, which in turn cause triglycerides (fats) to be stored. Therefore prioritize complex, unprocessed carbohydrates when eating carbohydrates. For sensitive individuals, this may also include avoiding some high glycemic fruits. Most weight loss programs get participants to avoid foods that elevate blood sugar, and therefore stimulate insulin to store fat.
The principle of weight loss through the avoidance of refined carbohydrates has been repeated in a long list of diet best sellers. Here are excerpts from several of them:
Dr. Dean Ornish, from Eat More, Weigh Less (1993):
Check out these links, and subscribe if you are interested:
Dr. Arya Sharma is currently the president of the Canadian Obesity Network, and you can find his blog at: http://www.drsharma.ca/ Check out his comments on the use of BMI as a valid indicator of excess body fat at: http://www.drsharma.ca/accuracy-of-bmi-for-diagnosing-obesity-2.html
Dr. Yoni Freehoff is a recognized expert in obesity in Ottawa, and a long time blogger on healthy diets. See his site, “Weighty Matters” here. Drs. Sharma and Friedhoff published a book on obesity management in 2010; Dr. Friedhoff is expecting to publish a new book shortly. http://www.weightymatters.ca/2013/01/the-new-england-journals-obesity.html
Interesting new lines of evidence are emerging about causes of obesity. Recently, it has been shown that bowel microflora can affect the development of obesity in humans and in mice. Another study of overweight young adults demonstrated that isocaloric diets that were low in fat were much less likely to stimulate both total and resting energy expenditure than diets that were low in carbohydrates, suggesting that not all calories are the same. A randomized control study lasting 2 years revealed that a low carbohydrate diet and a Mediterranean diet were as or more effective in weight loss and various health parameters than was a low-fat diet. These findings confirmed what was shown in the A to Z Diet study in 2007, where the Atkins diet had more favorable outcomes with every measure (including weight loss) than did the Zone Diet or the Ornish diet. The lead researcher at Stanford reviewed his findings in this video.