Eating lower-carb meals lowers insulin levels and promotes weight loss. (Louise Valentine/The Epoch Times)
In particular, while starchy carbs such as bread, potatoes, rice, pasta, and breakfast cereals have for a long time been promoted as wholesome, nutritious, and healthy, the reality is that they tend to be disruptive of blood sugar and insulin levels in a way that can predispose to all sorts of problems including weight gain, type 2 diabetes, and cardiovascular disease.
Those who traditionally criticize low-carb diets have often done this on the basis of safety. This is ironic because there is actually quite a stack of evidence that shows that lower-carb diets generally lead to significant improvement in certain markers for disease, including blood fat levels and measures of blood sugar status.
One such study was published in the online journal Nutrition and Metabolism. This study took 50 overweight or obese individuals, with an average body mass index 33.6, and randomized them to eat one of two test diets [1]. One of these diets was relatively low in protein and rich in carbohydrate.
The other was higher in protein (1.6 grams of protein per kilogram of body weight) and lower in carbohydrate (less than 170 grams of carbs compared to more than 240 grams in the other diet).
Both diets were calorie-restricted, supplying 500 calories less per day than the amount estimated to be required to maintain stable weight. The study lasted for four months.
At the end of the study, the higher-protein, lower-carb eaters had lost more weight (9.1 percent compared to 7.3 percent of those eating more carbohydrate and less protein), though the difference was not statistically significant. The group eating less carbs lost more fat than the higher-carb consumers, and this difference was statistically significant (8.7 percent versus 5.7 percent).
The improved fat loss is important here because it serves to remind us that gross weight loss tells us nothing about what actually has been lost. For individuals who are carrying extra fat, the fat is what needs shifting; the lower-carb diet was the clear winner here.
Why? Part of the explanation may lie in the fact that the lower-carb diet, in theory at least, should have led to lower levels of insulin, which happens to be the chief hormone responsible for fat deposition in the body.
Evidence, which supports this concept, comes from the finding in this study that the lower-carb diet led to lower insulin levels after eating compared to the higher-carb diet. The difference was statistically significant. Less insulin might not only mean less fat; it may well mean lower risk of type 2 diabetes in time, too.
Other statistically significant benefits of the higher-protein, lower-carb diet were seen in the levels of triglycerides, HDL-cholesterol, and LDL-cholesterol.
The authors of this study conclude: “A weight-loss diet with moderate carbohydrate and moderate protein results in more favorable changes in body composition, dyslipidemia, and post-prandial INS [insulin] response compared to a high-carbohydrate, low-protein diet, suggesting an additional benefit beyond weight management to include augmented risk reduction for metabolic disease.”
Common sense dictates that a generally healthy diet will be one that is similar to the diet we ate for longest in terms of our evolution on this planet. Why? Because that’s the diet we evolved to eat, and it’s therefore the diet we’re most likely to be best adapted to.
It is interesting to note that primitive diets have been found to contain considerably less carbohydrate and more protein than the sort of diet we typically eat now [2]. It is no wonder that rates of obesity and type 2 diabetes are rising as they are. And there’s certainly an argument for returning our diet to something more primal in nature.
References:
1. Walker Laser DA, et al. Moderate carbohydrate, moderate protein weight loss diet reduces cardiovascular disease risk compared to high carbohydrate, low protein diet in obese adults: A randomized clinical trial. Nutrition & Metabolism 2008, 5:30
2. Cordain L, et al. Plant-animal subsistence ratios and macronutrient energy estimations in worldwide hunter-gatherer diets. American Journal of Clinical Nutrition 2000 Mar; 71(3): 682—92
Dr. John Briffa is a London-based physician and author with an interest in nutrition and natural medicine.
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