Diet and Weight Loss
Nicely timed for the 2012 Olympic Games in London, the British Medical Journal (BMJ) has published several articles revealing the “truth about sports drinks.” That truth is this: drink when you are thirsty and don’t waste your money or calories on sports drinks—choose water instead. Before the rise of sports drinks, athletes (and the rest of us) drank water when we exercised or got sweaty. How did we know when to drink, or how much? The way humans have known for eons—thirst. But as the BMJ team describes, sports drink makers spent a lot of money sponsoring less-than-rigorous research damning thirst as a guide to hydration and casting doubt on water as the beverage for staying hydrated. The bottom line is that thirst remains an excellent gauge of hydration, and plain old water is still the best way to replace lost fluid.
By offering the taste of sweetness without any calories, artificial sweeteners seem like they could be one answer to effective weight loss. The American Heart Association (AHA) and American Diabetes Association (ADA) have given a cautious nod to the use of artificial sweeteners in place of sugar to combat obesity, metabolic syndrome, and diabetes, all risk factors for heart disease. As with everything, there’s more to the artificial sweetener story than their effect on weight. One concern is that people who use artificial sweeteners may replace the lost calories through other sources, possibly offsetting weight loss or health benefits. It’s also possible that these products change the way we taste food. Research also suggests they may prevent us from associating sweetness with caloric intake. In addition, the long-term effects of artificial sweeteners on health have not been fully determined.
If you start an exercise program, it only seems fair that you should see your hard work reflected in lower numbers on the scale. If it isn’t, don’t despair—or quit exercising. You are still helping your heart, lungs, and every other part of your body. A study in the Journal of the American College of Cardiology looked at the effects of exercise and/or weight loss on cardiovascular health among more than 3,000 men and women who were initially overweight. As I write in the July issue of the Harvard Health Letter, those who exercised consistently and lost weight had the biggest reduction in heart attack risk over six years of follow-up. Exercising without losing weight and losing weight without exercising offered smaller benefits. Although exercise and weight don’t always move in the same direction, they are both important for health.
For people who are obese, the operation known as gastric bypass surgery has been hailed as something of a miracle. In addition to rapid weight loss, it can reverse diabetes and reduce the risk of heart disease. A new study reveals potential darker side—an increase in alcohol abuse. In a presentation at yesterday’s annual meeting of the American Society for Metabolic and Bariatric Surgery, researchers reported that almost 11% of nearly 2,000 men and women who underwent gastric bypass surgery (the most common type of obesity surgery) got in trouble with drinking by the second year after surgery. About 7% drank too much before the operation, representing a 50% increase. This finding shouldn’t steer people who could benefit from gastric bypass surgery away from the procedure. But it should prompt them—and their doctors—to be on the lookout for changes in alcohol use or abuse afterward.
Red meat hasn’t been getting very good press lately. Meat-heavy diets have been linked to increased risks of developing heart disease, diabetes, and some cancers. New findings from two long-term studies now indicate that eating lots of meat, especially processed meat, may also shorten your life. The new research involved nearly 125,000 female nurses and male health professionals, whose diet and health have been followed by Harvard School of Public Health researchers for more than two decades. Compared to eating less than one serving a day of red meat, adding one daily serving increased the chances of dying during the study period by 13%. (A serving is three ounces, about the size of a deck of cards). Red meat meant beef, pork, lamb, and hamburger. For every extra serving of processed meat (foods like hot dogs, bacon, and cold cuts), the increase was 20%.
Exercise makes cells burn extra energy—that’s one way it helps control weight. It also generates a newly discovered hormone, called irisin, that transforms energy-storing white fat cells into energy-burning brown fat cells. Irisin also appears to help prevent or overcome cellular changes that lead to type 2 diabetes. The hormone does this by helping transform energy-storing white fat cells into energy-burning brown fat cells. White adipose tissue, more commonly known as body fat, is the tissue that dimples thighs, enlarges waists and derrieres, and pads internal organs. Each white fat cell stores a large droplet of fat. Brown fat, in comparison, is chock full of energy-burning mitochondria. Its main function is to generate body heat by burning fat. A team led by Dr. Bruce Spiegelman, professor of cell biology and medicine at Harvard Medical School, has identified irisin in mice and humans and showed how irisin transforms white fat cells into brown ones, at least in mice.
When you polish off a piece of chocolate cake and immediately start thinking about having another, you might suspect that eating for pleasure may trigger overeating. A new study out of Italy, where they know a thing or two about good food, supports this notion. Researchers from Naples and Salerno found that eating for enjoyment […]
Although short-term studies suggest that switching from sugar to calorie-free sweeteners can help people lose weight, the December 2011 Harvard Health Letter explores the possibility that it may actually promote weight gain. Use of super-sweet artificial sweeteners may desensitize users to sweetness. Healthful foods like fruits and vegetables may become unappetizing by comparison. As a result, the overall quality of the diet may decline. The calories removed from the diet by the sugar-for-sweetener swap may sneak back in, in the form of refined carbohydrates and low-quality fats. Another concern is that artificial sweeteners could cause weight gain by directly stimulating the development of new fat cells.
“Limit salt” has been a key part of dietary advice for decades. Once aimed at individuals, the FDA is hoping to persuade food companies to cut back on salt added to prepared foods. That’s probably a good idea, since the average American gets more salt—and thus sodium—than needed, most of it from prepared foods. But the question of how low we should go with sodium hasn’t been answered. Two studies suggest that getting too little sodium could pose problems, just as eating too much does. Trials to determine the safest range for sodium aren’t in the offing. What to do in the interim? Aiming for the recommended target of 2,300 milligrams per day from all sources is probably good for most people.
The new science of social networks is demonstrating how personal interconnections can affect our health. Ideas and habits that influence health for better or for worse can spread through social networks in much the same way that germs spread through communities. An article in the December issue of the Harvard Men’s Health Watch explores how social networks can affect weight and mood. A study of people taking part in the Framingham Heart Study found that among participants who had a friend become obese, their chance of becoming obese rose by 57%. A different study from Framingham showed that happiness can also spread across social networks. Research into social networks could help experts some day use them to improve public health.