News to Empower you

BY DACE TRENCE, MD, FACE

Have you tried the soup diet to lose weight? What about the grapefruit diet or the fruit only diet?

The reason any of these “single food” diets work is that, as humans, psychologically we get very tired of one food only and begin to skip or even avoid that food until the temptation to eat something “different” becomes overwhelming, and we start all over again.

At medical meetings this past year, an interesting study was presented in which the effect of fasting on alternate days was examined. The fasting was defined as skipping meals and snacks except for either one meal specific to a time of day or having many small meals instead of three major meals.

Study participants with a BMI (body mass index, a measure of body fat based on height and weight) of over 30 (defined as obese) were able to lose weight following an alternate day fasting or limited meal program. The study was short (only eight weeks), participants were physically inactive or moderately active and had to have a stable weight over time. The researchers randomized participants to have a single meal as lunch on the fast day, a single meal as dinner on the fast day, or small meals throughout the day as a fast day meal. It should be noted that the fast day meals were limited to just 500 calories and were 25 percent to 30 percent total fat, 15 percent to 20 percent protein and 50 percent to 60 percent carbohydrates, and included 30 milligrams of cholesterol and 5 to 10 g fiber. The people in the dinner meal group lost the most weight, followed by the multiple small meals group, followed by the lunch group. And when compared to participants that were advised to cut down their overall calorie intake, the results were the same.

Take-home message: Whether you cut your calories every day or approach your weight management program with every-other-day calorie restriction, both programs can work. Chose the one that fits your lifestyle and preference.

In another study, investigators took a look at what role our brain plays in our eating behaviors. It’s not surprising that these brain signals might then be modified to affect appetite.

Researchers enrolled participants into three groups: lean, nondiabetic and obese, or obese and diabetic. Each of these three groups consisted of eight men and eight women, and the participants had a mean age of 58. The study used a technique called functional MRI (fMRI), a means of looking at brain changes to specif ic challenges. Participants had three fMRI sessions each. In each session, after fasting overnight, they were given an intravenous injection consisting of either a placebo or a drug in the class called glucagon-like peptide-1 (GLP-1) receptor agonist before and after drinking chocolate milk or a tasteless solution. After the fMRI scans, the participants could help themselves to a buffet, and their food intake was monitored.

Compared with the lean participants, the obese participants had increased activation in the brain’s reward system when they anticipated receiving chocolate milk and decreased activation in the brain’s reward system after they actually drank the chocolate milk. Changes were seen in the brain areas regulating reward, appetite and motivation.

And these changes in brain activation appeared to play a role in how much food was subsequently eaten from the buffet. After the injection of the active drug, lean and obese, nondiabetic participants decreased their food intake by about 25 percent. Those who were both obese and diabetic decreased their caloric intake by 14 percent.

Study participants who received injections of the GLP-1 receptor agonist showed decreased responses in the brain’s reward system at the sight of chocolate milk. Additionally, if the participants drank the chocolate milk, their brain responses seemed more sensitized to the milk, so less was drunk.

Again, this was a small study, but the findings indicate that GLP-1 may play a role in the brain regarding anticipation of tasty food, and thus may reduce food cravings. The GLP-1 agonist also increased activation in the brain’s reward system after eating food, which may prevent overeating. Earlier research has shown that compared with lean individuals, obese individuals have increased activation of the brain’s reward system when they see pictures of appetizing food, but they have decreased activation in the areas of the brain when they eat satisfying food, which may lead to overeating.

Take-home message: We still have a lot to learn about what is involved in appetite to, in turn, then be able to change it. And further information as to how one drug class could differently affect the brain in different types of individuals makes this area of research even more challenging!

Finally, from a very recent report in the diabetes literature, the question was raised as to what we should consider as optimal benefits of exercise in those having diabetes mellitus type 2 (the diabetes that results from insulin not working as it should, combined by a loss of insulin production over time). As physicians, we typically look not just at weight loss and blood sugar control, but also at fitness as a measure of benefit from exercise. It’s not surprising that those in this study who exercised had lower body fat, smaller waist size and better blood sugar control than people who did not exercise. And the benefits of exercise were seen whether it was aerobic exercise, resistance training or a combination of the two.

Yet about 30 percent of people who exercise are considered non-responders, meaning they do not improve their level of fitness despite regular exercise. But these “non-responders” did show improvements in their weight, were able to loose body fat, and had better blood sugars—their bodies clearly did benefit and respond to exercise.

Take-home message: Some individuals with type 2 diabetes who exercised did not show improvement in their fitness, but still gained other very positive health benefits, suggesting that the medical definition of “non-responder” is too narrow. So take note if you read that some who exercise are “non-responders” – it really depends on what definition of benefit is being used. Look closely and you will see that there are always some positive changes that come from exercise. So turn the TV off, shut down the computer, and get those walking shoes on! Dr. Dace Trence is Director of the Diabetes Care Center and Professor of Medicine at the University of Washington Medical Center in Seattle. She is also the University of Washington Endocrine Fellowship Program Director and Director of Endocrine Days, a medical education program for endocrinologists practicing in the Pacific Northwest. She is on the American College of Endocrinology Board of Trustees and chairs the CME Committee and is also chair of the AACE Publications Committee.

Dr. Dace Trence is Director of the Diabetes Care Center and Professor of Medicine at the University of Washington Medical Center in Seattle. She is also the University of Washington Endocrine Fellowship Program Director and Director of Endocrine Days, a medical education program for endocrinologists practicing in the Pacific Northwest. She is on the American College of Endocrinology Board of Trustees and chairs the CME Committee and is also chair of the AACE Publications Committee.