Can timing of meals help with weight loss?
This is a story about the importance of good timing.
Two-thirds of Americans are overweight or obese. This excess weight contributes to a variety of health problems. Despite enormous effort over decades, the problem has proved extremely difficult to solve. Biologist Satchin Panda thinks we’re missing a key variable: Instead of focusing so much on what we eat, he says, we should pay more attention to when we eat.
A researcher at the Salk Institute in San Diego, Panda argues that eating within a certain time window each day can help people lose weight and may help prevent illnesses including diabetes, heart disease and cancer. In animal studies, he and others have shown that limiting food intake to a period of eight to 12 hours can boost cognitive and physical performance, and may even lengthen life span. Known as time-restricted feeding, or TRF, the approach is simple: Eat more or less what you want, but don’t consume anything before or after the allotted time.
Panda argues that humans’ circadian rhythm is not designed for a world with 24-7 access to food. “If you’re eating all the time, it messes up that pattern,” he says. For many if not most Americans, that pattern is deeply out of whack, and many of us eat from early morning until late at night.
It is not clear whether TRF works in humans the way it seems to work in lab mice. For one, mice and humans have very different circadian rhythms. Mice are nocturnal and sleep more than once a day. They also live for only two or three years. “It may be that for a mouse, a 16-hour fast is the equivalent of a two- or three-day fast for a human,” says Courtney Peterson, a nutrition scientist at the University of Alabama at Birmingham who is doing research on TRF in humans.
In addition, Peterson and others say, some of the benefits of TRF may stem from decreased con-
Dear Dr. Roach: My husband is physically fit and works out daily through biking, elliptical trainer, playing hockey, working outside, etc. He is of appropriate weight, and his cholesterol and sugar numbers are normal, as is his blood pressure. What concerns me is his diet. Every day, he eats meat — red meat, pork or chicken. He also eats lunch meat and plenty of cheese. He says working out counters the effect of these foods. He has a heart murmur, and his father passed away unexpectedly from either a heart attack or stroke at age 74 this past summer. Can all of this add to his potential to have a heart attack, or do the test results indicate that he is fine? — J.M.
Answer: To be optimally healthy, both exercise and diet are important. People argue passionately about what is the healthiest diet and whether eating red meat is healthy. Although some people have seized on newer study results, I have read many studies in the past 30 years, and believe that eating less meat and more fruits, vegetables, whole grains, legumes, nuts and seeds, and fish is much healthier. In my opinion, your husband’s eating habits do contribute to heart attack risk despite his exercise regimen. I also should add that processed meats have been convincingly linked to increased cancer risk; however, the magnitude of that risk is small.
That does not mean he has to change his eating habits entirely in order to get healthier; small changes are more likely to be acceptable to him. Starting with one meal a day of fish or creatively cooked plants (some people find mushrooms, for example, a very good meat substitute) can help reduce his risk.
Dear Dr. Roach: Iam a 77-year-old man. A year ago, I was diagnosed with atrial fibrillation. I went to a cardiologist, who performed a nuclear stress test, an echocardiogram and two 24-hour EKGs (Holter monitors). I was treated with metoprolol and Eliquis. The issue is that I exercise six days a week. I have absolutely no symptoms, and am wondering whether these medications are of any benefit. My cardiologist recommends continuing with both to avoid a stroke. During exercise, my heart rate will occasionally rise to over 170 beats per minute. Do you have any comments? — M.G.
Answer: I would comment that there are several benefits to treatment. As your cardiologist noted, people with atrial fibrillation are at a higher risk for stroke, and apixaban (Eliquis) is one treatment that helps reduce that risk. So, I certainly would recommend continuing that medication, if your cardiologist has decided it’s right for you (some people with atrial fibrillation are treated with warfarin; others with aspirin, instead of apixaban and similar drugs).
A second goal is keeping the heart rate in a safe zone. Very fast heart rates (which often can be seen in atrial fibrillation) can cause symptoms, lower blood pressure to dangerous levels and cause damage to the heart muscle. A heart rate of 170 in a 77-year-old man is higher than I am comfortable with, and higher than most published recommendations I have read. Metoprolol, a beta blocker, slows heart rate but is better at slowing resting heart rate than exercise-induced heart rate. I certainly wouldn’t recommend stopping or lowering the metoprolol, and I would be sure that your cardiologist knows your heart rate at peak exercise.