Are all calories the same for weight loss? Well, maybe not.
Conventional wisdom tells us that weight loss is simply about burning more calories than you consume. But recent research has begun to debunk that notion with reports that the quality of food (or calorie) is just as important as the quantity when it comes to weight loss.
In the past year, researchers at the New Balance Foundation Obesity Prevention Center at Boston Children’s Hospital conducted two studies looking at how food composition affects our metabolism, brain activity, and blood sugar levels, and in turn our weight loss efforts.
The first study tracked 21 overweight and obese adults over several months as they completed a standard weight-loss diet (losing 10-15% of their body weight), and then moved on to a low-fat, low-carbohydrate, or low-glycemic-index diet one month at a time. Based on the traditional line of thinking there shouldn’t be any difference in weight loss because all three diets had the same amount of calories (just from varied sources of food), but the results weren’t that cut and dry.
Instead, the researchers found that each of the diets had marked differences on participants’ total energy expenditure (TEE), or the amount of calories they burned naturally each day. When compared to the low-fat diet, those on the low-carb diet burned 300 more calories daily, and those on the low-glycemic-index diet burned an extra 150 calories per day, enhancing weight loss efforts. Additionally, the low-fat and low-carb diets had negative effects on blood lipid profiles (e.g., cholesterol), stress- and weight-related hormones, and other chemicals that can impact your weight and health.
The second study looked at the effect of high-glycemic foods on the brain. Twelve overweight or obese men were given similar-tasting milkshakes with the same amount of calories, carbohydrates, protein, and fat, but one was made with high-glycemic corn syrup and the other with low-glycemic sugars.
As expected, the high-glycemic milkshakes led to a faster spike in blood sugar. Even more telling was that 4 hours after drinking the high-glycemic milkshake, blood sugar levels dropped to the hypoglycemic range with the men complaining of more hunger pangs and their brain scans showing greater stimulation in the nucleus accumbens, the brain’s center for regulating cravings, rewards, and addictive behaviors.
This finding is significant because previous studies have suggested that refined carbohydrates more intensely affect this region (particularly in the brains of obese people), which may generate more intense food cravings and positive feelings of reward after eating high- caloric and glycemic foods, leading to overeating.
Moreover, research has shown that plummeting blood sugar levels drives people to consume high-glycemic foods (simple carbs) to restore levels as quickly as possible. This cycle of blood sugar levels ebbing and flowing can easily result in overeating and weight gain.
All in all, what these studies tell us is that counting calories alone is not the key to weight loss. It’s actually more complicated than that and the kinds of foods you eat can have a serious consequence on your metabolism, blood sugar levels, and brain chemistry, which all influence your eating behavior and weight. So the next time hunger strikes, skip the 100-calorie snack pack of chocolate chip cookies and reach for a high-fiber, low-glycemic food like a 100-calorie apple to help your weight loss efforts behind the scenes.