Take this fruit and eat it! You’ll be doing your heart and your midsection a favor.
Fruits? Veggies? Carbs? Leading nutrition researcher Walter Willett explains what you should fork up (and push aside) to cut your risk of cancer, heart disease, type 2 diabetes, and more.
Our expert, Walter Willett, MD, PhD, is the chairman of the Department of Nutrition at the Harvard School of Public Health. Since 1976, he’s directed the Nurses’ Health Study dietary investigation, tracking the food, lifestyle diaries, and health records of 121,000 nurses, plus another 116,000 younger nurses who joined the study in 1986. It’s the biggest, longest-running national research program, and has yielded dozens of findings, from the link between trans fats and heart disease to the new respect for whole-grain foods. Author of Eat, Drink, and Be Healthy (Free Press, 2002), he’s taken on the USDA to change the food pyramid and has successfully lobbied food companies to get the trans fats out of your food.
Q. In the nearly 30 years you’ve been involved with the Nurses’ Health Study, what have you learned that we can use to improve our health?
A. What you eat matters. Even more than the number of calories you consume. That’s become clear in our data in the Nurses’ Health Study in ways I didn’t even anticipate at the beginning.
With heart disease, for example, in the late ’70s, we were really focused on cholesterol and saturated fat. But it’s turned out that these are really a small part of the picture.
Instead, trans fat [the solid, partially hydrogenated fat found in fried foods, some margarines, and baked goods] is a far more important risk factor for heart disease. So is eating an excess of refined carbohydrates and sugar. And, in a twist, eating unsaturated fats, particularly the omega-6 and omega-3 polyunsaturated types, can substantially reduce the risk of heart disease as well as type 2 diabetes.
Q. Are there links between our diets and the kind of cancers we tend to get?
A. The most important nutrition-related factor with cancers is excess weight. That wasn’t appreciated or understood 10 years ago. After quitting smoking, weight control is the next most important thing you can do to keep your cancer risk low.
Eating a diet high in fruits and vegetables won’t protect you from cancer. But for heart disease, fruits and vegetables do turn out to be beneficial, so it’s still good to eat them. There is quite good evidence that eating lots of red meat and, particularly, processed meat, may boost your risk of colon cancer. Inadequate folic acid is also related to colon cancer and probably breast cancer, particularly in those people who are moderate drinkers.
But the top line is weight: We see that the risk and death rates of breast cancer in the U.S. could be roughly cut in half if women didn’t gain weight during midlife.
Obesity, Weight Loss, and Carbs
Q. Is obesity truly a health crisis among middle-aged women?
A. I prefer phrasing it as a healthy weight-control issue rather than an obesity issue. The word obesity tends to stigmatize the extremely overweight person. And it’s not just the extremely overweight person who’s at high risk; it’s the average person in the United States, who tends to be just a few pounds overweight, who is fueling the increasing level of adverse health outcomes.
As a country, we need to find a healthier way to live than we have now, where weight gain starts in childhood and continues through our entire life. It’s better to start early, but you can still benefit by losing a few pounds at age 50 or 60 or even 70.
Q. So it’s absolutely not acceptable to gain weight as you age?
A. That’s my point. What we consider to be the typical increase with age, that gradual pound-or-two-a-year creep, can add up to a substantial health risk in a relatively short period of time.