Medical Compass: Weight management is less about macronutrient intake than you think

Lowering cortisol levels can help manage weight

By David Dunaief, M.D.

Losing or maintaining body weight is complex. Many things influence our eating behavior, including food addictions, boredom, lack of sleep and stress.

While calorie intake is an important element of the equation, knowing a food’s caloric impact doesn’t always make a difference in our behavior. Studies assessing the impact of nutrition labeling in restaurants gave us a good picture of this complex issue: knowing an item’s calories either doesn’t alter behavior or can actually encourage higher calorie purchases (1, 2).

The good news is that controlling weight isn’t only about exercising willpower and skipping higher calorie items. Instead, we should focus on our diet’s composition.

Increasing food quality has a tremendous impact. This is not about emphasizing on macronutrient over another. Macronutrient categories are protein, carbohydrates, and fats. Instead, it’s about emphasizing micronutrients over macronutrients. Micronutrients, simply, are vitamins and minerals in foods. Foods that are micronutrient-dense tend to be the most satisfying. In a week to a few months of emphasizing micronutrients, one of the first things my patients notice is a significant reduction in macronutrient cravings.

Balancing protein, carbohydrates and fats

Many diets focus on the balance of macronutrients. Which has the greatest impact on weight loss? In a randomized control trial (RCT), when comparing different macronutrient combinations, there was very little difference among study groups, nor was there much success in helping obese patients reduce their weight (3, 4). Only 15 percent of patients achieved a 10 percent reduction in weight after two years.

The four different macronutrient diet combinations involved overall calorie restriction. In addition, each combination had either high protein, high fat; average protein, high fat; high protein, low fat; or low protein, low fat. Carbohydrates ranged from low to moderate (35 percent) in the first group to high (65 percent) in the last group. This was another well-designed study, involving 811 participants with an average BMI of 33 kg/m², which is classified as obese.

Focusing primarily on macronutrient levels and calorie counts did very little to improve results.

Should we avoid refined carbohydrates?

A small RCT showed refined carbohydrates actually may cause food addiction (5). MRI scans of trial subjects showed that certain sections of the brain involved in cravings and reward are affected by high-glycemic foods.

Study participants consumed a 500-calorie shake with either a high-glycemic index or a low-glycemic index. They were not told which they were drinking. The ones who drank the high-glycemic shake had higher levels of glucose in their blood initially, followed by a significant decline in glucose levels and increased hunger four hours later. The region of the brain that is related to addiction, the nucleus accumbens, showed a spike in activity with the high-glycemic intake.

The authors note that this effect may occur regardless of the number of calories consumed. Commonly found high-glycemic foods include items like white flour, sugar, and white potatoes. We should all strive to limit or avoid refined carbohydrates.

Focusing on micronutrients 

In an epidemiological study looking at National Health and Nutrition Examination Survey data, results demonstrate that those who are overweight and obese tend to be micronutrient-deficient (6). This can have long-term impacts on your health that are not just related to weight. Micronutrients include carotenoids, such as lutein, zeaxanthin, beta-carotene, alpha-carotene and beta-cryptoxanthin, as well as vitamin B12, folate and vitamins C, E and D.

Unfortunately, taking supplements doesn’t solve the problem; generally, micronutrients from supplements are not the same as those from foods. With a few exceptions, such as vitamin D and potentially B12, most micronutrient levels can be raised by increasing the variety of foods in your diet. Please, ask your doctor before starting or stopping supplements.

Cortisol levels and weight

While cortisol is important to an array of physiological processes, including regulating inflammation and blood pressure, too much cortisol can cause health problems. There is a complex dynamic between cortisol and weight. Cortisol raises glucose blood levels and is involved in promoting visceral or intra-abdominal fat. This type of fat coats internal organs. Decreasing your level of cortisol metabolite might also result in a lower propensity toward insulin resistance and decrease your risk of cardiovascular mortality.

In a preliminary, small, prospective (forward-looking) study involving women, results show that once obese patients lost weight, the levels of cortisol metabolite excretion decreased significantly (7). This is encouraging. Controlling or losing weight is more complex than calorie-counting. While calorie intake has a role, food’s nutrient density may play a significant role in reducing your cravings, ultimately helping you manage your weight.

References:

(1) Am J Pub Health 2013 Sep 1;103(9):1604-1609. (2) Am J Prev Med.2011 Oct;41(4):434–438. (3) N Engl J Med 2009 Feb 26;360:859. (4) N Engl J Med 2009 Feb 26;360:923. (5) Am J Clin Nutr Online 2013;Jun 26. (6) Medscape General Medicine. 2006;8(4):59. (7) Clin Endocrinol.2013;78(5):700-705.

Dr. David Dunaief is a speaker, author and local lifestyle medicine physician focusing on the integration of medicine, nutrition, fitness and stress management. For further information, visit www.medicalcompassmd.com or consult your personal physician.