What causes someone to become overweight or obese?

You can become overweight or obese when you eat more calories (KAL-oh-rees) than you use. A calorie is a unit of energy in the food you eat. Your body needs this energy to function and to be active. But if you take in more energy than your body uses, you will gain weight.
Many factors can play a role in becoming overweight or obese. These factors include:
Behaviors, such as eating too many calories or not getting enough physical activity
Environment and culture.

Genes
Overweight and obesity problems keep getting worse in the United States. Some cultural reasons for this include:
Bigger portion sizes
Little time to exercise or cook healthy meals
Using cars to get places instead of walking


What are the health effects of being overweight or obese?
Being overweight or obese can increase your risk of:
Heart disease
Stroke
Type 2 diabetes
High blood pressure
Breathing problems
Arthritis
Gallbladder disease
Some kinds of cancer
illustration of a pear- and apple-shaped woman

But excess body weight isn't the only health risk. The places where you store your body fat also affect your health. Women with a "pear" shape tend to store fat in their hips and buttocks. Women with an "apple" shape store fat around their waists. If your waist is more than 35 inches, you may have a higher risk of weight-related health problems.

What is the best way for me to lose weight?
The best way to lose weight is to use more calories than you take in. You can do this by following a healthy eating plan and being more active. Before you start a weight-loss program, talk to your doctor.

Safe weight-loss programs that work well:
Set a goal of slow and steady weight loss — 1 to 2 pounds per week
Offer low-calorie eating plans with a wide range of healthy foods
Encourage you to be more physically active
Teach you about healthy eating and physical activity
Adapt to your likes and dislikes and cultural background
Help you keep weight off after you lose it

How can I make healthier food choices?
The U.S. Department of Health and Human Services (HHS) and Department of Agriculture (USDA) offer tips for healthy eating in Dietary Guidelines for All Americans.
Focus on fruits. Eat a variety of fruits — fresh, frozen, canned, or dried — rather than fruit juice for most of your fruit choices. For a 2,000-calorie diet, you will need 2 cups of fruit each day. An example of 2 cups is 1 small banana, 1 large orange, and 1/4 cup of dried apricots or peaches.

Vary your veggies. Eat more:
dark green veggies, such as broccoli, kale, and other dark leafy greens
orange veggies, such as carrots, sweet potatoes, pumpkin, and winter squash
beans and peas, such as pinto beans, kidney beans, black beans, garbanzo beans, split peas, and lentils
Get your calcium-rich foods. Each day, drink 3 cups of low-fat or fat-free milk. Or, you can get an equivalent amount of low-fat yogurt and/or low-fat cheese each day. 1.5 ounces of cheese equals 1 cup of milk. If you don't or can't consume milk, choose lactose-free milk products and/or calcium-fortified foods and drinks.
Make half your grains whole. Eat at least 3 ounces of whole-grain cereals, breads, crackers, rice, or pasta each day. One ounce is about 1 slice of bread, 1 cup of breakfast cereal, or 1/2 cup of cooked rice or pasta. Look to see that grains such as wheat, rice, oats, or corn are referred to as "whole" in the list of ingredients.
Go lean with protein. Choose lean meats and poultry. Bake it, broil it, or grill it. Vary your protein choices with more fish, beans, peas, nuts, and seeds.
Limit saturated fats. Get less than 10 percent of your calories from saturated fatty acids. Most fats should come from sources of polyunsaturated and monounsaturated fatty acids, such as fish, nuts, and vegetable oils. When choosing and preparing meat, poultry, dry beans, and milk or milk products, make choices that are lean, low-fat, or fat-free.
Limit salt. Get less than 2,300 mg of sodium (about 1 teaspoon of salt) each day.

How can physical activity help?
The new 2008 Physical Activity Guidelines for Americans state that an active lifestyle can lower your risk of early death from a variety of causes. There is strong evidence that regular physical activity can also lower your risk of:
Heart disease
Stroke
High blood pressure
Unhealthy cholesterol levels
Type 2 diabetes
Metabolic syndrome
Colon cancer
Breast cancer
Falls
Depression

Regular activity can help prevent unhealthy weight gain and also help with weight loss, when combined with lower calorie intake. If you are overweight or obese, losing weight can lower your risk for many diseases. Being overweight or obese increases your risk of heart disease, high blood pressure, stroke, type 2 diabetes, breathing problems, osteoarthritis, gallbladder disease, sleep apnea (breathing problems while sleeping), and some cancers.
Regular physical activity can also improve your cardiorespiratory (heart, lungs, and blood vessels) and muscular fitness. For older adults, activity can improve mental function.

Physical activity may also help:
Improve functional health for older adults
Reduce waistline size
Lower risk of hip fracture
Lower risk of lung cancer
Lower risk of endometrial cancer
Maintain weight after weight loss
Increase bone density
Improve sleep quality

Health benefits are gained by doing the following each week:
Moderate activity
During moderate-intensity activities you should notice an increase in your heart rate, but you should still be able to talk comfortably. An example of a moderate-intensity activity is walking on a level surface at a brisk pace (about 3 to 4 miles per hour). Other examples include ballroom dancing, leisurely bicycling, moderate housework, and waiting tables.

Vigorous activity
If your heart rate increases a lot and you are breathing so hard that it is difficult to carry on a conversation, you are probably doing vigorous-intensity activity. Examples of vigorous-intensity activities include jogging, bicycling fast or uphill, singles tennis, and pushing a hand mower.
2 hours and 30 minutes of moderate-intensity aerobic physical activity
or
1 hour and 15 minutes of vigorous-intensity aerobic physical activity
or
A combination of moderate and vigorous-intensity aerobic physical activity
and
Muscle-strengthening activities on 2 or more days
This physical activity should be in addition to your routine activities of daily living, such as cleaning or spending a few minutes walking from the parking lot to your office.
If you want to lose a substantial (more than 5 percent of body weight) amount of weight, you need a high amount of physical activity unless you also lower calorie intake. This is also the case if you are trying to keep the weight off. Many people need to do more than 300 minutes of moderate-intensity activity a week to meet weight-control goals.

How you can increase your physical activityIf you normally... Try this instead!
Park as close as possible to the store Park farther away
Let the dog out back Take the dog for a walk
Take the elevator Take the stairs
Have lunch delivered Walk to pick up lunch
Relax while the kids play Get involved in their activity