Cutting back on carbohydrates can help shrink a bulging midriff.

Pants getting a little snug? It's not just you: Americans' waistlines have ballooned over the past decade or so, to an average of just under 40 inches for men and almost 38 inches for women, according to a large federal study.

Some plastic bottles, food containers, and linings of cans contain bisphenol A (BPA), a chemical that's been under close scrutiny because of its potential effects on human health. Most Americans have traces of BPA in their urine, and some research hints of a possible link between BPA exposure and cardiovascular disease. Now, a study in the September 2014 Hypertension finds that BPA exposure from cans may raise blood pressure.

Sixty older adults drank two servings of soymilk provided one of three ways: in two glass bottles (providing the least BPA), two cans (most BPA), or one glass bottle and one can. Two hours after participants drank from the cans, their urinary BPA levels were much higher than after they drank from two glass bottles. And their systolic blood pressure (the first number in a blood pressure reading) was roughly 4.5 mm Hg higher after two cans versus two glass bottles.

The proper role of fat in diet is not that complicated.

Atkins, South Beach, paleo, high-protein, low-carb, gluten-free—the march of the media darlings of dieting never ceases, along with the scientific controversy over which one works best. But for many health-conscious men, maintaining a lean physique isn't the only consideration when making dining decisions. What diet protects you best from heart disease and stroke?

Just as regular exercise has a host of health benefits for the body, staying mentally active appears to preserve memory and general sharpness. But for getting a good night's sleep, light workouts for both body and brain may be best, according to a study in the Journal of the American Geriatrics Society.

The study focused on 72 people, ages 67 to 79, who reported poor sleep as well as declining mental sharpness. They were assigned at random to do either strenuous aerobic exercise or a gentler stretching routine, paired with either watching educational DVDs (followed by short quizzes) or engaging in more demanding computer-based brain training.

Mindfulness has garnered tremendous interest over the past decade. Research suggests that mindfulness — the ability to live each moment as it unfolds and accept it without judgment — can help reduce stress and enhance health.

Perhaps one of the greatest psychological benefits of interacting with a dog is the opportunity it provides to be more mindful — to purposely focus your attention on the present moment.

The most conclusive evidence shows that combining activities that benefit body and soul also reduces the risk of dementia.

Q. I am more than an inch shorter than I was a few years ago, but my weight has remained constant. I noticed that my body mass index (BMI) is just above 25. Does that mean than I am now overweight even though I haven't put on any pounds?

A. Technically, it does. Generally, people with a BMI between 25 and 30 are considered overweight, and those with a BMI of 30 and over are considered obese.

Even if you don't swim, exercising in the water can improve your strength, balance, and cardiovascular fitness. And it's easier on your joints.

The Mediterranean diet consistently has been linked with an array of health benefits, including decreased risk of heart disease, diabetes, dementia, and cancer. In a study published online Dec. 2, 2014, by the medical journal BMJ, researchers at Harvard-affiliated Brigham and Women's Hospital linked the Mediterranean diet to longer life as well. The researchers analyzed information from 4,676 healthy women in the Nurses' Health Study who had completed a food questionnaire and whose telomere lengths had been measured. (Telomeres are repetitive DNA sequences at the ends of chromosomes that get shorter every time a cell divides, and thus are markers of cell aging.) They found that a greater adherence to the Mediterranean diet was associated with longer telomeres, and that even small changes in diet made a difference. In effect, the women who had followed the Mediterranean diet were biologically younger than those who hadn't.

The Mediterranean diet is rich in fruits, vegetables, whole grains, olive oil, nuts, seeds, beans, and legumes. Animal protein is furnished by seafood and moderate amounts of poultry, eggs, and dairy. Red meat and sweets are considered occasional treats. This study gives another reason to follow this healthy—and tasty—eating plan.

Quick-start strength-training program

Work out at home or in your office to improve muscle mass.

Muscle mass tends to diminish with age, so making strength training part of your overall exercise regimen is very important. And while many people assume that effective strength-training programs require joining expensive fitness clubs and lifting heavy weights, there are plenty of strength-building exercises you can do at home and at work with little or no special equipment. "You really can strength train without the big machines and get effective results, without spending a lot of money," says Elissa Huber-Anderson, a physical therapist at Harvard-a-ffiliated Massachusetts General Hospital.