A new study published today in the Journal of the American Medical Association challenges the notion that “a calorie is a calorie. The study at the New Balance Foundation Obesity Prevention Center Boston Children’s Hospital,

finds diets that reduce the surge in blood sugar after a meal–either low-glyceamic index or very-low carbohydrate-may be preferable to a low-fat diet for those trying to achieve lasting weight loss.

Weight re-gain is often attributed to a decline in motivation or adherence to diet and exercise, but biology also plays an important role. After weight loss, the rate at which people burn calories (known as energy expenditure) decreases, reflecting slower metabolism. Lower energy expenditure adds to the difficulty of weight maintenance and helps explain why people tend to re-gain lost weight.

Reducing refined carbohydrates may help maintain weight loss better than reducing fat

Prior research by Ebbeling and Ludwig has shown the advantages of a low glycemic load diet for weight loss and diabetes prevention, but the effects of these diets during weight loss maintenance has not been well studied. Research shows that only one in six overweight people will maintain even 10 percent of their weight loss long-term.

The study suggests that a low-glycemic load diet is more effective than conventional approaches at burning calories (and keeping energy expenditure) at a higher rate after weight loss.

“We’ve found that, contrary to nutritional dogma, all calories are not created equal,” says Ludwig, also director of the Optimal Weight for Life Clinic at Boston Children’s Hospital. “Total calories burned plummeted by 300 calories on the low fat diet compared to the low carbohydrate diet, which would equal the number of calories typically burned in an hour of moderate-intensity physical activity,” he says.

Each of the study’s 21 adult participants (ages 18-40) first had to lose 10 to 15 percent of their body weight, and after weight stabilization, completed all three of the following diets in random order, each for four weeks at a time. The randomized crossover design allowed for rigorous observation of how each diet affected all participants, regardless of the order in which they were consumed:

• — A low-fat diet, which reduces dietary fat and emphasizes whole grain products and a variety of fruits and vegetables, comprised of 60 percent of daily calories from carbohydrates, 20 percent from fat and 20 percent from protein.

• — A low-glycemic index diet made up of minimally processed grains, vegetables, healthy fats, legumes and fruits, with 40 percent of daily calories from carbohydrates, 40 percent from fat and 20 percent from protein. Low glycemic index carbohydrates digest slowly, helping to keep blood sugar and hormones stable after the meal.

• — A low-carbohydrate diet, modeled after the Atkins diet, comprised of 10 percent of daily calories from carbohydrates, 60 percent from fat and 30 percent from protein.

The study used state-of-the-art methods, such as stable isotopes to measure participants’ total energy expenditure, as they followed each diet.

Each of the three diets fell within the normal healthy range of 10 to 35 percent of daily calories from protein. The very low-carbohydrate diet produced the greatest improvements in metabolism, but with an important caveat: This diet increased participants’ cortisol levels, which can lead to insulin resistance and cardiovascular disease. The very low carbohydrate diet also raised C-reactive protein levels, which may also increase risk of cardiovascular disease.

Though a low-fat diet is traditionally recommended by the U.S. Government and Heart Association, it caused the greatest decrease in energy expenditure, an unhealthy lipid pattern and insulin resistance.

“In addition to the benefits noted in this study, we believe that low-glycemic-index diets are easier to stick to on a day-to-day basis, compared to low-carb and low-fat diets, which many people find limiting,” says Ebbeling. “Unlike low-fat and very- low carbohydrate diets, a low-glycemic-index diet doesn’t eliminate entire classes of food, likely making it easier to follow and more sustainable.”

 

They’re among the earliest known foods. Archaeological evidence suggests that tree nuts were a major part of the human diet 780,000 years ago. Several varieties of nuts, along with the stone tools necessary to crack them open, have been found buried deep in bogs in the Middle East. Rich in energy and loaded with nutrients, nuts and, particularly, their cargo of omega-3 fatty acids are thought to have been essential to the evolution of the large, complex human brain.

Researchers have long linked consumption of tree nuts, despite their significant fat content, to decreased risk of cardiovascular disease, obesity, diabetes, cancer and even Parkinson’s disease.

Now comes evidence that they also improve cognition in general and specific ways. Most have high concentrations of vitamin E, the B vitamins (including folate), antioxidants, minerals such as magnesium, as well as omega-3 fats, all of which support myriad functions of the nervous system.

Researchers find that eating a high concentration of walnuts (half a cup a day) boosts inferential verbal reasoning, especially the ability to distinguish true from false. An array of compounds in walnuts, including vitamin E, folate, melatonin and varied antioxidative polyphenols, protect the central nervous system and speed synaptic transmission. The significant supply of alpha-linolenic acid is essential for stability of neuronal membranes, through which all neuronal actions transpire.

Almonds may help save your memory.

Mice rendered temporarily amnesiac were more apt to remember their way around a maze 24 hours later if they first consumed an almond paste.

The evidence suggests that almonds slow the decline in cognitive abilities linked to Alzheimer’s disease. Investigators attribute the memory effects to the presence of the essential amino acid phenylalanine and L-carnitine, believed to boost neurotransmitters essential to memory.

For the world’s 20 million diabetics, almonds may improve blood- sugar control while decreasing the risk of cardiovascular disease. In a randomized controlled study, a team of Chinese and American researchers found that four weeks of an almond-augmented diet improved blood lipid levels, abolished a postprandial rise in glucose levels and reduced body fat in 20 patients with Type 2 diabetes. The magnesium, fiber, monounsaturated fat and polyphenols in the nuts all contribute to the improvements in glycemic control.

Brazil nuts can spare the obese the vascular damage associated with adiposity.

An excess of fat tissue stimulates low-grade inflammation and oxidative stress, both of which can lead to cardiovascular disease.

With high levels of unsaturated fatty acids and bioactive substances that combat inflammation — selenium, phenolic compounds, folate and magnesium among them — Brazil nuts improved microcirculation, lowered cholesterol levels and normalized blood lipid profiles without causing weight gain in 17 obese female adolescents.

Pecans may slow the rate of age-related motor degeneration. University of Massachusetts scientists fed two versions of a nut- rich diet to rats specifically bred to develop motor-neuron decline. All pecan-fed animals outperformed control animals on subsequent tests of activity, and those fed the highest percentage of nuts outran them all. The researchers believe the high concentration of antioxidant vitamin E shields neurons from degenerative conditions such as amyotrophic lateral sclerosis or Lou Gehrig’s disease.

A review and meta-analysis reported in the May 9, 2012 issue of the Journal of the American Medical Association found a protective effect for orally-administered probiotics against diarrhea that often develops as a response to antibiotic drugs.

While antibiotics destroy harmful as well as beneficial bacteria, probiotics consist of beneficial live microorganisms whose presence in the digestive tract can help prevent the overgrowth of unhealthy organisms.

Susanne Hempel, PhD, of the research organization RAND Health in Santa Monica, California and her colleagues reviewed 82 randomized clinical trials of patients receiving antibiotics that compared the effects of a probiotic to no treatment, a placebo, or a different probiotic or probiotic dose. A pooled analysis of 63 of the trials, which included a total of 11,811 participants, concluded that the use of probiotics was associated with a 42 percent lower risk of developing diarrhea as a result of antibiotic use compared to not consuming probiotics. Because many types and blends of probiotics were used in the studies, it was difficult to identify which strains were responsible for the benefits observed, however, pooled analyses limited to trials of Lactobacillus, Saccharomyces and Streptococcus probiotics were associated with risk reductions of 36%, 52% and 49%, respectively.

“We found a clear beneficial effect of probiotics in preventing or treating antibiotic-associated diarrhea,”

stated study coauthor Sydne J. Newberry, who is a nutritional scientist and a researcher at RAND. “The pooled evidence suggests that probiotics are associated with a reduction in antibiotic-associated diarrhea,” the authors conclude.

Working rotating shifts increases the risk of type 2 diabetes in women, according to two prospective cohort studies published in December 2011 by Harvard School of Public Health scientists.

Previous studies have found that working rotating shifts is associated with various health concerns, such as weight gain and metabolic syndrome. So it makes sense that this new study found equally harmful effects.

Researchers evaluated 69,269 women aged 42 to 67 years old who were participating in the Nurses’ Health Study I, and 107,915 women aged 25 to 42 years in the in Nurses’ Health Study II. The researchers determined at the beginning of the study how long the subjects had worked rotating shifts, defined as at least three nights per month in addition to days and evenings in that month. This was updated every two to four years in the Nurses’ Health Study II group. The study authors also administered a validated questionnaire to the subjects that confirmed self-reported type 2 diabetes.

According to the study, shift work was associated with an increase in the likelihood of type 2 diabetes. The subjects who reported working rotating shifts for one to two years had an increase in the likelihood of type 2 diabetes by five percent. Subjects who worked rotating shifts for three to nine years had their risk of type 2 diabetes increase by 20 percent, while 10 to 19 years of rotating shifts was associated with a 40 percent increased risk and 20 or more years with a 58 percent risk.

The researchers concluded that an extended period of rotating night shift work is associated with a modestly increased risk of type 2 diabetes in women, which appears to be partly mediated through body weight.

Previous research also indicated that low levels of melatonin, the key hormone that regulates circadian rhythms, are associated with suboptimal blood sugar metabolism. Furthermore, melatonin is a potent antioxidant and protects the pancreatic beta-cells that secrete insulin from oxidative damage.