Two new studies presented at the Endocrine Society’s 91st Annual Meeting in Washington DC offer additional evidence for the value of a low-carb diet, not just for weight loss, but for overall health.
In the first study, researchers showed that even a modest reduction in carbohydrates was enough to both stabilize blood sugar and reduce insulin levels. (Both are extremely important for reducing the risk of diabetes.)
Researchers assigned one group of participants a “standard” diet of 55% carbohydrates (typical in America) while a second group was given a “moderate” carb diet of 43% carbs. Both diets had the same amount of calories, and approximately the same amount of protein (roughly 18% of calories). To keep calories the same, and to make up for the calories lost by reducing carbohydrates, the “Moderate Carb’ dieters ate more fat (39% of calories) than the “standard” diet (27% of calories).
The subjects received just enough calories to maintain their weight at pre-study levels. The subjects were weighed every day (except weekends) and if someone lost or gained weight, his calories were adjusted so that he could maintain his original weight.
Even in the absence of weight loss there were significant changes for the moderate carb group. The modest reduction in carbs from 55% to 43% resulted in lowered insulin levels and stabilized blood sugar. And the moderate-carb dieters reported feeling fuller after eating breakfast- and staying fuller for a longer time- than those eating the standard “high carb” diet.
It’s reasonable to expect that if the researchers had added a weight loss component to the study design, the moderate carbers would have been more successful, if for no other reason than they felt fuller after eating their lower-carb meals. “Over the long run a sustained modest reduction in carbohydrate intake may help to reduce [food] consumption and facilitate weight loss,” said Barbara Gower, PhD, a coauthor of the study.
In the second study Israeli researchers evaluated 56 overweight or obese men and women who were otherwise healthy with no history of diabetes or cardiovascular disease. They fed the subjects on four different mornings. Each morning the subjects were given a different food or beverage with a wide range of glycemic indexes, from zero (water) to 100 (pure glucose). In descending order of glycemic index, the “breakfasts” consisted of 1) pure glucose, 2) cornflakes, 3) high fiber cereal and 4) water.
Both before and after the “meals” (or the water), the researchers looked at the functioning of the endothelium– the layer of cells that lines the inside of the blood vessels—using a test called flow-mediated dilation (FMD). Endothelial function is very important and is an excellent indicator of the health of the vascular system. If endothelial function is poor, the risk of heart disease is substantially higher than when endothelial function is good. The researchers also measured the subjects’ blood sugar levels.
Previous research has demonstrated that having high blood sugar after meals is a definite risk factor for cardiovascular disease, both in patients with diabetes and in the general population as well. And poor endothelial function is an important risk factor for heart disease.
Both blood sugar levels and endothelial function were considerably worsened in those eating the high-glycemic foods (glucose and cornflakes). According to the authors, the high-glycemic meals “appear to impair the endothelial function”.
“Based on our study, we urge consumers to have low-glycemic index carbohydrates instead of high-glycemic carbohydrates for better health”, said Dr. Michael Shechter, senior cardiologist at The Sackler Faculty of Medicine at Tel Aviv University.
Taken together these two studies add to the weight of the evidence that low-glycemic eating has enormous health benefits.
The Atkins Nutritional Approach has always been about eating whole foods with the lowest-glycemic impact. The basic principles of the Atkins Nutritional Approach include low sugar, adequate protein, healthy fat and high fiber, with zero trans fats, and plenty of vitamins, minerals and antioxidants from the healthiest foods on earth: that’s the perfect low-glycemic eating plan for a healthy long life.
