Weight management

Weight management means reaching and keeping a weight that supports your health. It is about how you feel and how your body works, not about appearance, and the number on the scale is only one part of the picture. This page covers what a healthy weight means, what helps, what doesn't, and what to do if you need to gain weight rather than lose it.

What a healthy weight means

The most common starting point is the body mass index (BMI), your weight in relation to your height. For adults, a BMI under 18.5 is classed as underweight, 18.5 to 24.9 as a healthy weight, 25 to 29.9 as overweight, and 30 or more as obesity.

BMI is a screening tool, not a diagnosis. It can't tell muscle from fat, and the same BMI can mean different things for different people. Waist size adds useful information, because fat around the middle carries more health risk; a waist above 35 inches for women or 40 inches for men is a common warning sign. Your doctor will also look at blood pressure, blood sugar and cholesterol, and at how you feel day to day. For more on the health side, see obesity and health.

What helps

There are no shortcuts, but there is good evidence for a few things, and they work best together.

An eating pattern you can keep. Losing weight means taking in somewhat less energy than you use, but the type of diet matters less than whether you can stick with it. Mediterranean-style, vegetarian, lower-fat and lower-carb approaches can all work. Most people find it easier with plenty of vegetables, fruit, whole grains, beans and protein, and less in the way of sugary drinks, sweets, ultra-processed snacks and alcohol. Our guide to eating to lose weight goes into the details.

Regular physical activity. US guidelines recommend at least 150 minutes a week of moderate activity, such as brisk walking, plus muscle-strengthening activity on two days a week. Activity on its own leads to modest weight loss, but it matters a great deal for keeping weight off and for health at any weight. Start where you are: a 15-minute walk counts, and building up gradually helps avoid injury.

Sleep and stress. Short sleep and long-term stress are linked to weight gain, and both make healthy habits harder to keep.

Support. Structured programs, registered dietitians and behavioral counseling help many people more than going it alone.

Small losses count. Losing 5% of your body weight, which is 10 pounds for someone who weighs 200, can improve blood pressure, cholesterol and blood sugar. Losing about 1 to 2 pounds a week makes it more likely that the weight stays off.

Medical treatment

For some people, lifestyle changes aren't enough on their own. Doctors can prescribe weight-loss medicines, including newer drugs such as semaglutide and tirzepatide, and for people with severe obesity, bariatric surgery may be an option. These decisions are made with a doctor, who weighs the likely benefits against side effects, cost and other health conditions. The medicines work best alongside healthy eating and activity, and weight usually comes back if they are stopped.

What doesn't work

Weight-loss supplements. In the US, supplements don't need FDA approval before they go on sale. The FDA has found hundreds of weight-loss products with hidden drug ingredients, including sibutramine, a prescription medicine withdrawn in 2010 because of the risk of heart attack and stroke. Be wary of any product that promises quick or guaranteed results.

Cleanses, detoxes and crash diets. Very low-calorie plans can take weight off fast, but most of it comes back, and they can leave you short of nutrients. See what the evidence says about juice fasting.

Keeping weight off

The body tends to defend its weight. After weight loss, appetite often rises and the body burns slightly fewer calories, which is why habits you can live with matter more than a short, strict diet. People who keep weight off tend to stay active, eat regular meals, keep an eye on their weight, and get back on track quickly after a lapse.

When you need to gain weight

For some people the challenge is the opposite. A BMI under 18.5, weight loss during illness or recovery, or a poor appetite in older age can all affect health, from weaker immunity to loss of muscle and bone. Gaining weight healthily means adding nourishing calories rather than junk food: more frequent meals and snacks, nuts and nut butters, whole milk or yogurt, eggs, olive oil, avocado and beans, along with strength exercise to build muscle. Unexplained weight loss should always be checked by a doctor.

Sources

• Steps for losing weight (US Centers for Disease Control and Prevention)
• Prescription medications to treat overweight and obesity (National Institute of Diabetes and Digestive and Kidney Diseases)
• Beware of products promising miracle weight loss (US Food and Drug Administration consumer update)
• Physical Activity Guidelines for Americans, 2nd edition (US Department of Health and Human Services)

Last reviewed November 2026. This article is general information, not medical advice.