MY AIM IN THIS SITE is to oﬀer straightforward, no-nonsense advice on nutrition based on the best information available. I’ll start right here: If your weight is in the “healthy” range, keep it there. If you are overweight, do your best to avoid adding any more pounds and lose some if you can. This isn’t a new idea, it isn’t sexy, and it certainly won’t land me a spot as the next fad diet guru on The Oprah Winfrey Show. But next to whether you smoke, the number that stares up at you from the bathroom scale is the most important measure of your future health. Keeping that number in the healthy range is more important for long-term health than the types and amounts of antioxidants in your food or the exact ratio of fats to carbohydrates. So this chapter will focus mostly on the amount of food you eat rather than the type of food. In the rest of the book I will explain what foods to choose for maximum health.
Weight sits like a spider at the center of an intricate, tangled web of health and disease. Three related aspects of weight—how much you weigh in relation to your height, your waist size, and how much weight you gain after your early twenties—strongly inﬂuence your chances of having or dying from a heart attack, stroke, or other type of cardiovascular disease; of developing high blood pressure, high cholesterol, or diabetes; of being diagnosed with postmenopausal breast cancer or cancer of the endometrium, colon, or kidney; of having arthritis; of being infertile or having trouble getting an erection; of developing gallstones; of snoring or suﬀering from sleep apnea; or of developing adult-onset asthma. As shown in Figure 4, weight is directly linked with a variety of diseases in the Nurses’ Health Study. With increasing body mass index—more about that later—the risks of heart disease, high blood pressure, gallstones, and type 2 diabetes all steadily increase, even among those in the healthy weight category. Above a body mass index of 30, which is the boundary between overweight and obesity, the risks continue to increase. Similar trends are seen among men in the Health Professionals Follow-up Study.
Given the importance of weight in staying healthy, no mention of weight in the USDA Food Guide Pyramid for a decade has been a serious omission. What’s more, weight recommendations in the current Dietary Guidelines for Americans are set too high for many people and may mislead some into thinking that substantial weight gains within the “healthy” weight categories are perfectly ﬁne .
THE OBESITY EPIDEMIC
Excess weight is a very personal problem. It shapes how you feel about yourself and how others treat you. It has a direct impact on your current and future health. It costs you (or at least your health insurance company) tens of thousands of dollars more in medical costs over the years. Excess weight is also a major public health problem. If current trends continue, we could call the ﬁrst decade of the new millennium the obesity decade. Since the early 1960s, the proportion of Americans who are moderately overweight has stayed the same, hovering just over 30 percent. What has changed dramatically, though, is the number who are obese. About one-third of Americans now fall into this category, more than double the proportion from the early 1960s. Obesity among children is also on the rise, an alarming trend given that early obesity leads to diabetes and cardiovascular disease at a young age. As a nation, we spend more than $90 billion a year on medical care for obesity and its complications.
The situation isn’t much better elsewhere around the
globe. The World Health Organization calls obesity a worldwide epidemic. And though deadly famines and starvation make headlines, overweight, obesity, and their health consequences have begun replacing undernutrition and infection as the main causes of early death and disability in many developing countries.
learn more: Eat, Drink, and Be Healthy!
WHAT IS A HEALTHY WEIGHT?
What seems to be a simple question turns out to be remarkably diﬃcult to answer. Part of the problem is that a weight that may be perfectly ﬁne for someone who is six feet one—say, 175 pounds—is way too much for someone who is ﬁve feet one. Another part is lingering confusion from the way healthy weights have been deﬁned in the past.
A number called the body mass index, or Quetelet index, gets around the ﬁrst problem. This measure of weight adjusted for height does a good job of accounting for the fact that taller people tend to weigh more than shorter people. If you like math, you can calculate your body mass index, or BMI, like this: Divide your weight in pounds by your height in inches; divide that number by your height in inches; and multiply that number by 703. You can also just look it up in the table on page or have it calculated for you by any number of online BMI calculators, such as the one on the Harvard Health Publications Web site Setting guidelines for healthy BMIs has traditionally been done by examining death rates in large groups of people and then picking those BMIs with the lowest death rates as the “healthy range.” This usually gives a U-shaped curve with increasing death rates on either side of some minimum. These curves imply that weighing too little is just as unhealthy as weighing too much.
learn more: Building a Better Pyramid
There’s certainly no argument about the too-much-weight side. Countless studies, one of which includes more than a million adults, have shown that BMIs above 25 increase the risk of dying early, mainly from heart disease and cancer. There is widespread agreement that BMIs from 25 up to 30 should be considered overweight and over 30 obese. It’s the too-little-weight side of the curve, however, that has caused confusion.