Micronutrient deficiency and obesity are intertwined
By David Dunaief, M.D.
If you’re trying to lose weight, you’re probably closely watching your calorie intake. We’ve been trained for a lifetime to scrutinize calories and to exercise more willpower in avoiding high-calorie options.
However, the road to weight loss, or even weight maintenance, is complex. Many things influence our eating behavior, including food addictions, boredom, lack of sleep and stress.
Awareness of a food’s caloric impact doesn’t always matter, either. Studies assessing the impact of nutrition labeling in restaurants gave us a clear view of this issue: knowing an item’s calories either doesn’t alter behavior or can encourage higher calorie purchases (1, 2).
The good news is that success is not solely about willpower. Instead, we need to change our diet composition.
In my clinical experience, increasing the quality of food has a tremendous impact. Foods that are the most micronutrient dense, such as plant-based foods, rather than those that are focused on macronutrient density, such as protein, carbohydrates and fats, tend to be the most satisfying. In a week to a few months of focusing on micronutrients, one of the first things patients notice is a significant reduction in cravings.
What is the impact of refined carbohydrates?
Generally, we know that refined carbohydrates don’t help. Looking deeper, a small, randomized control trial (RCT) showed refined carbohydrates actually may cause food addiction (3). Certain sections of the brain involved in cravings and reward are affected by high-glycemic foods, as shown by MRI scans of trial subjects.
Study participants consumed a 500-calorie shake with either a high-glycemic index or a low-glycemic index. They were blinded (unaware) as to 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.
According to the authors, 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. The conclusion: Everyone, but especially those trying to lose weight, should avoid refined carbohydrates.
Do macronutrients matter?
We tend to focus on macronutrients — protein, carbohydrates and fats — when looking at diets. But are these the elements that have the greatest impact on weight loss? In an 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 (4, 5). 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.
Again, focusing primarily on macronutrient levels and calorie counts did very little to improve results.
What’s the relationship between micronutrients and weight?
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). 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 without supplementation, by adding variety to your diet. Please ask your doctor.
How do cortisol levels affect health?
The good news is that once people lose weight, it may be easier to continue to keep the weight off. In a prospective (forward-looking) study, results show that once obese patients lost weight, the levels of cortisol metabolite excretion decreased significantly (7).
Cortisol raises blood-levels of glucose and is involved in promoting visceral or intra-abdominal fat. This type of fat can coat internal organs, such as the liver, and result in nonalcoholic fatty liver disease. Decreasing the level of cortisol metabolite may also result in a lower propensity toward insulin resistance and may decrease the risk of cardiovascular mortality. This is an encouraging preliminary, yet small, study involving women.
Controlling or losing weight is not solely about willpower or calorie-counting. While calorie intake has a role, the nutrient density of the food may be more important to your success and may play a significant role in reducing cravings, ultimately helping to manage weight in the long run.
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) Am J Clin Nutr Online 2013;Jun 26. (4) N Engl J Med 2009 Feb 26;360:859. (5) N Engl J Med 2009 Feb 26;360:923. (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.
