Diet & Weight Loss Archive

Your BMI estimates your body fat better than the number on a scale. But a tape measure is an equally important tool.

As your BMI rises above 25, so does your risk for developing high blood pressure, diabetes, and cardiovascular disease.
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The body mass index (BMI), a measurement derived from the relationship between your weight and your height (see box), is a common way to estimate body fat. It's a simple, fast, and essentially free tool that enables doctors to help identify people who might be at risk for health problems—including cardiovascular disease—that are linked to excess body fat.

Many people cite a lack of “motivation” or “willpower” as the reason that overweight people can’t control their eating habits. But a wealth of evidence has come to light that obesity is linked to insufficient sleep. Most recently, an experimental study has found that restricted sleep can increase the levels of brain chemicals that make eating pleasurable. Could it be that insufficient sleep makes the brain addicted to the act of eating?

Ask anyone who’s ever tried to make a healthy change — after a while, the motivation to keep at it just stops. Indeed, it can be incredibly hard to break old habits, or make new ones. But research has revealed that there are actually two different types of rewards in the brain — and that focusing on the less commonly pursued of the two can help you make lasting changes.

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The popular eating pattern that's good for your heart—the Mediterranean diet—is also good for your waistline, according to a review of five studies that compared the Mediterranean diet with other weight-loss diets.

The trials, which included a total of 998 overweight or obese people, pitted the Mediterranean diet (which is rich in vegetables, fruits, grains, beans, and olive oil but light on meat, dairy, and eggs) against one or more of three other diets: a low-fat diet, a low-carb diet, and the American Diabetes Association (ADA) diet.

The USDA recently updated its recommendations for healthy eating. Here are the takeaway messages for men.

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Every five years, the USDA releases its Dietary Guidelines for Americans—advice to encourage healthier eating patterns based on the latest nutritional science.

"While there is a lot of nutritional information out there, the guidelines are the foundation for many government food programs, and many men can benefit from their recommendations," says Katherine McManus, director of the Department of Nutrition at Harvard-affiliated Brigham and Women's Hospital.

Ask the doctor

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Q: My doctor advised me to give up my soda habit, but I was thinking about switching to diet soda. What is your advice about the safety of artificial sweeteners?

A: I support your decision to decrease the amount of added sugar in your diet, but it is less clear if artificial sweeteners are the answer. These sugar substitutes do appear to be safe when consumed in usual amounts. Initial studies in rats, performed decades ago, raised a possible link to bladder cancer, but no subsequent studies in humans have confirmed this relationship.

The final recommendations do not specify limiting consumption of red and processed meats, which have been linked to cancer risk.

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The report of the Dietary Guidelines Advisory Committee, released in February 2015, suggested that the then-forthcoming update to the Dietary Guidelines for Americans adopt several changes from previous versions. It advised limiting added sugars to 10% of calories; removing the ceiling on dietary fats as long as saturated fat comprises no more than 10% of calories; and limiting consumption of red and processed meat.

When the final guidelines were released by the Department of Health and Human Services (HHS) and the Department of Agriculture (USDA) in January 2016, the caveat on red and processed meat was missing. Through that omission, the guidelines "censored conclusions of the scientific advisory committee," according to a statement on the website of the Harvard T.H. Chan School of Public Health. Dr. Frank Hu, Harvard professor of nutrition and epidemiology, was a member of the federal Dietary Guidelines Advisory Committee, which spent two years reviewing reams of scientific evidence on diet and health and drafting the guidelines that were submitted to HHS and USDA. "Although there are some areas of improvement in this edition over previous ones, some simple but important recommendations are watered down, especially reducing consumption of red and processed meat," he says.

Ask the doctors

Q: I just read that we shouldn't be getting more than 10% of our calories from sugar. Should I cut back on fruit?

A: While it's a good idea to limit sugars from processed foods, you can worry less about eating too much fruit. In fact, one small study found no ill effects in people who ate 20 servings of fruit a day for 12 to 24 weeks.

This ancient practice can transform the way you think about food and set the stage for a lifetime of healthy eating.

Like most of us, you've probably eaten something in the past few hours. And, like many of us, you may not be able to recall everything you ate, let alone the sensation of eating it. According to a 2011 report from the U.S. Department of Agriculture, the average American spends two-and-a-half hours a day eating, but more than half the time, we're doing something else, too. Because we're working, driving, reading, watching television, or fiddling with an electronic device, we're not fully aware of what we're eating. And this mindless eating—a lack of awareness of the food we're consuming—may be contributing to the national obesity epidemic and other health issues, says Dr. Lilian Cheung, a nutritionist and lecturer at Harvard T.H. Chan School of Public Health.

In the journals

Even if you are active, increasing the time you spend standing every day may further lower your odds of becoming obese, says a new study from the American Cancer Society.

The researchers studied more than 7,000 patients, ages 20 to 79, and reviewed the association between their standing time and their risk of obesity. They looked at specific measurements—such as body mass index, waist circumference, and body fat percentage—and metabolic syndrome, a clustering of factors that increases the risk for heart disease, stroke, and diabetes.