Nutrition Archive

News briefs

Nuts are rich in healthy fat and calories, so you may not think of them as tools for weight control. But nuts may actually help in the battle of the bulge, suggests a Harvard study published online Sept. 23, 2019, by BMJ Nutrition, Prevention, and Health. Researchers analyzed questionnaire responses on dietary habits, physical activity, and weight changes from about 145,000 middle-aged and older men and women. People who went from never eating nuts to eating a daily average of at least half a serving (about half a handful) were 16% less likely to become obese over a four-year period compared with people who didn't eat nuts at all. Substituting a half serving of nuts per day for red meat, processed meat, French fries, desserts, or potato chips was also associated with less weight gain. "Nuts have protein and fiber which help us feel full longer and offset cravings for junk food. Although nuts are high in calories, up to 20% of calories from nut consumption will be excreted from our body," says Dr. Xiaoran Liu, one of the study authors and a research associate with the Harvard T.H. Chan School of Public Health.

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If you enjoy butter on your baked potato, toast, or pasta, you've probably felt a pang of guilt when putting that golden pat on your plate. Or worse, you may feel conflicted and confused as to whether you should stick with butter or switch to margarine or another spread.

Although a staple of the American diet, butter came under a great deal of scrutiny when its high levels of saturated fat were associated with increased heart disease risk. Many people accepted the demise of butter in stride, ruing the loss of its savory flavor but agreeing that its effect on the heart might be too high a price to pay. They dutifully switched to margarine, as researchers and nutritionists suggested. Then the hazards of margarine came to light. The older margarines had high levels of trans fats that packed a double whammy for heart disease by raising levels of LDL (bad cholesterol) and lowering levels of HDL (good cholesterol). Many people felt betrayed or duped.

Researchers examining dietary data from over 50,000 postmenopausal women found that women who ate foods with a higher glycemic index, and foods with more added sugars, were more likely to have insomnia.

Eating more unprocessed, plant-based foods is one of the best ways you can protect your heart.

What do you usually eat for breakfast? How about for lunch and dinner? These questions are standard fare during a consultation with Dr. Ron Blankstein, a preventive cardiologist at Harvard-affiliated Brigham and Women's Hospital. The answers help him tailor the dietary advice he gives, which can have a profound effect on the future health of his patients' hearts.

"Most people really aren't aware of the importance of a healthy diet, or they're confused about what they should be eating," says Dr. Blankstein. About five years ago, he revamped his own diet to follow what the current evidence suggests is the best way to avoid heart disease: a whole-food, plant-based style of eating. "I find that when I tell my patients I follow this diet myself, they're far more likely to buy into it," he says. (For an idea of what he typically eats, see "A day of plant-based meals.")

Ask the doctor

Q. Just before the holidays, I heard that a study said it was okay to eat red meat. Previously, you've said just the opposite. Help!

A. We got lots of letters like yours. The bottom line is that we stick by our longstanding advice: avoid frequent meals of red meat, and especially processed meat.

Research we're watching

Replacing just one sugary drink each day with water may reduce your risk of developing diabetes, according to a study published online Oct. 3, 2019, by Diabetes Care. Researchers from Harvard's T.H. Chan School of Public Health looked at more than two decades' worth of data collected in three long-term studies, involving more than 192,000 adults. By tracking beverage intake over time, they found that people who increased their consumption of sugary drinks (including 100% fruit juice) by more than 4 ounces a day over four years had a 16% increase in diabetes risk over the next four years. Turning to "diet" versions might not help, either: an 18% jump in diabetes risk occurred in people who increased their intake of artificially sweetened drinks by more than 4 ounces a day over the same period, although some of that risk could have reflected other factors, said researchers.

The bottom line: If you want to reduce diabetes risk, it's better to skip sweet drinks and stick to unsweetened tea, coffee, or water. When people drank one of those beverages once a day instead of a sweetened drink, diabetes risk dropped by 2% to 10%.

Editor's note: This year, we're highlighting grains and seeds on this page. Starting in February, we'll showcase a different grain or seed every month, with nutritional information and suggestions for adding these healthy foods into your diet. Here's some general background about these plant-based foods and why they're beneficial for cardiovascular health.

What, exactly, is a whole grain? Technically, they're dry, hard seeds of plants. Some are from grasses known as cereal grains, such as wheat, rice, corn, and oats. Others are from plants in different botanical families, such as quinoa, amaranth, and buckwheat, known as pseudo grains or pseudo cereals. A whole grain is one that contains all three layers of the grain kernel: the bran, the endosperm, and the germ.