Dairy weight-loss ads misleading

Several large-population studies showed a link between lower body weight and consumption of dairy products. Predictably, the dairy industry jumped on these studies and touted milk and cheese as a key to weight control and a new weapon in the obesity epidemic. One of the first things you learn in beginning statistics is that a high relationship between two variables doesn’t mean that one causes another. In other words, the fact that milk drinkers are thinner doesn’t mean that you will lose weight by drinking milk. Amy Joy Lanou from the University of North Carolina, Asheville reviewed 49 clinical trials and concluded that increasing consumption of dairy products or calcium did not help people lose weight. In studies finding a link, weight loss was probably due to increased exercise, reduced intake of high-calories foods, lifestyle changes, or increased intake of fiber, fruit and vegetables. Over consumption of dairy products will probably make you fatter, not thinner. (Nutririon Reviews, 66: 272-279, 2008).

High protein diets suppress ghrelin and appetite

The proportion of protein, carbohydrates and fats in a diet might influence weight gain. High protein diets decrease appetite and promote weight gain better than mixed or high carbohydrate diets at least for the first six months of dieting. High-fat, low-protein diets promote weight gain. Ghrelin, a hormone secreted by the stomach and pancreas, increases appetite. A University of Washington school of medicine study by Karen foster Schubert and colleagues showed that high protein foods suppressed ghrelin more than other kinds of nutrients and that fats suppressed it the least. The authors concluded that high protein/low-carbohydrate diets might promote weight loss by suppressing ghrelin, while high-fat diets promote weight gain because they do not reduce ghrelin levels. Ghrelin is only one factor controlling bodyweight and appetite.
Metabolic hormones such as insulin, glucagons and growth hormone; environmental temperature; fat cell hormones such as leptin; and gut hormones such as cholecystokinin and peptide YY also influence it. (Journal Clinical Endocrinology Metabolism, 93: 1971-1979, 2008)

Higher doses of growth hormone build muscle and reduce fat best

Celebrities such as Sylvester Stallone helped make growth hormone (GH) popular with the beautiful people and aging baby boomers. GH builds muscle, cuts fat and strengthens connective tissue, which makes aging people look and feel better. However, we don’t understand how the hormone works over time. Australian researchers, in a study on growth hormone-deficient adults, found that GH builds lean body mass slowly and that high doses (6 micrograms per kilogram bodyweight per day) were more effective for building muscle and decreasing fat than low doses (3 micrograms per kilogram bodyweight per day). Initially, GH increases protein synthesis and decreases the use of proteins and amino acids for fuel. The researchers concluded that GH is more effective at higher doses and that changes in muscle mass takes many weeks to occur. People who experienced early changes in protein synthesis at the cell level during treatment showed larger increases in muscle mass later in the study. Also, GH worked better in younger than older people. (Growth Hormone & IGF Research, 18: 55-64, 2008)

Weight loss does not reduce the number of fat cells

So, you lost 35 pounds of ugly fat and think those rolls around your middle are a distant memory. Think again. While you might have shrunk the cells, you didn’t get rid of them. They lie dormant like old land mines ready to explode your waistline if you overeat or stop exercising. Researchers at the Karolinska Institute in Stockholm, Sweden found that people keep the same number of fat cells throughout life and that fat cell number is fixed during childhood. More important, the body destroys and grows new fat cells continuously. Every year the body turns over about 10 percent of the fat cells. Also, while you can’t get rid of fat cells, you can create new ones. Fat cells fill with fat to a certain level and trigger the development of new fat cells that also stay with you. Drug companies should work on drugs that prevent fat cell regeneration rather than fight the losing battle of preventing fat accumulation in existing cells. (Nature, published online may 8, 2008)

Supplement industry opposes increased FDA scrutiny

Glaxo Smith Kline petitioned the food and drug administration (FDA) to require weight-loss supplement makers to support their claims with scientific research before their products hit the market. Not surprisingly, representatives of the supplement industry are up in arms over the petition and fear that increased FDA regulation could spread to other types of supplement. The dietary supplement health and education act of 1994 (DSHEA) gave supplement companies the right to market natural products without having to do safety and effectiveness trials. The FDA could only ban the products if there was scientific evidence showing significant risk to public health. The petition by the drug giant goes against the basic philosophy of DSHEA. We support removing supplements from the market if there is objective scientific evidence that they are unsafe we deplore the FDA using its power to water down DSHEA, a law supported by the people, approved by the congress and Senate and signed by the president. (The Tan Sheet, may 18, 2008)

Whole grains are good for the waistline

The government’s nutritional guidelines of 2005 recommended that Americans eat more whole grains and legumes. These foods are high in nutrients and fiber, which helps control appetite, blood sugar and satiety (satisfaction of hunger). However, the average person considers whole grains fattening and often eliminates them from the diet. Australian researchers summarize the literature on the effects of whole grains and legumes on the control and prevention of obesity. High consumption of these foods is linked to a reduced risk of heard diseases, obesity and diabetes, but scientists do not understand the mechanisms. The health benefits might be related to fiber content, glycemic index (simple or complex carbs), nutrient density, or their effects on the gut bacteria. Most studies on whole grains and health rely on dietary habits of large populations and their relationships to diseases. A relationship between two variables does not mean that one variable causes another. We have very few studies demonstrating that increasing whole-grain intake reduces body fat. However, the few studies we have are extremely promising. Long-term studies of people who lost weight and kept it off showed that their diets are high in complex carbohydrates and low in fat. Almost all of these “successful losers” also exercise an average of 1 hour per day. (Nutrition Reviews, 66: 171-182, 2008)

Why does CLA reduce fat better in animals than in humans

Conjugated linoleic acid (CLA) is one of the hottest weight-loss supplements on the planet. Almost every month, scientists publish a new study showing that it breaks down fat and prevents new fat formation. Unfortunately, most of these studies used animals (mainly mice). Studies of CLA use in humans showed less fat loss than animals or none at all. Why the difference? Melanie Plourde and colleagues from the University of Sherbrooke in Canada speculated that research difficulties are at the heart of the problem. Mice live only a few years and body composition control is much less complex than in humans. Factors such as age, gender, CLA dose and the type of CLA (CLA isomers) might account for the difference between animal and human studies. Also, scientists have little understanding of how CLA could cause fat breakdown in humans. (Nutrition Reviews, 66: 415-421, 2008)

Sleep problems linked to obesity

Manu bodybuilders snore or wake up frequently in the night because their large neck muscles obstruct airflow in the mouth and throat. If you have these symptoms, you might have a condition called sleep apnea that could make you fat or even kill you. Inadequate sleep caused by sleep apnea contributes to obesity. With sleep apnea, people stop breathing periodically during the night, which causes restless sleep and daytime drowsiness. This is an extremely dangerous condition that can result in automobile accidents and result and fatal disturbances in heart rhythms. Obesity also contributes to sleep apnea because extra tissue and poor muscle tone in the throat block the airway during sleep. Excess body fat alters the metabolism, which also interferes with normal sleep patterns. Sleep apnea and poor metabolic health often become a vicious cycle, because sleep apnea contributes to the metabolic syndrome and insulin resistance, which promote obesity and makes the sleep apnea worse. The metabolic syndrome is a group of symptoms linked to cardiovascular diseases that include high blood pressure, abdominal fat deposition, abnormal blood fats, insulin resistance, type 2 diabetes, inflammation and blood-clotting abnormalities. Sleep apnea is treatable through weight loss, surgery, or continuous positive airway pressure devices (CPAP). See you doctor if you have trouble sleeping or suffer from day time drowsiness, because sleep apnea can kill you. (Obesity Reviews, 9:340-354, 2008)