Doctors define obesity as excessive or abnormal fat accumulation that may harm health. Ways to help prevent obesity can include maintaining lifestyle factors such as a balanced diet, physical activity, and getting enough sleep.

Obesity may affect someone’s health by increasing the risk of conditions such as cardiovascular disease and diabetes. A healthcare professional may diagnose a person with obesity if they have a body mass index (BMI) of 30 or more.

In the United States, almost 3 in 4 adults ages 20 or older have overweight or obesity, and nearly 1 in 5 children and teenagers ages 2–19 years have obesity.

A person may be able to prevent obesity if they do not consume more calories, or energy, than they are using by maintaining healthy eating behaviors and regular physical activity. However, other factors can influence energy use, including stress and sleep quality.

State and local strategies are necessary for reducing obesity on a larger scale. A range of experts, including policymakers, schoolteachers, and healthcare professionals, are collaborating to help prevent obesity through education and healthy weight programs.

This article discusses several lifestyle habits that may help prevent obesity and when someone should speak with a doctor.

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A healthy, balanced diet is not about following short-term restrictions but making sustainable changes. This may involve reducing the intake of foods with high calorie but low nutrient content and increasing low calorie foods with high nutritional value.

The Dietary Guidelines for Americans 2020–2025 recommend including the following within the diet:

The guidelines also recommend limiting the following:

A person should speak with a doctor before making significant changes to their diet.

Nutrition resources

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Children and adolescents should participate in at least 1 hour of physical activity each day. This includes active play and moderate to intense physical activity, including aerobic exercise and activities to strengthen the bones and muscles.

Recommendations for adults are either of the following:

  • minimum of 150 minutes of moderate exercise per week
  • minimum of 75 minutes of vigorous exercise per week

People should also aim to participate in muscle-strengthening activities of moderate or greater intensity and that
involve all major muscle groups on 2 or more days a week for additional health benefits.

A person should speak with a healthcare professional about how to exercise safely.

Maintaining a moderate weight involves consistently eating well and participating in regular physical activity.

A person can speak with a doctor about how to safely and effectively maintain a moderate weight. A healthcare professional may recommend keeping a food and exercise journal when establishing a routine.

Each individual responds to stress differently, but evidence suggests that stress increases the risk of obesity. This may be due to the association between stress and low sleep duration and high glycemic (GI) food intake. It may also be related to the effect on hormone activity.

For example, the stress hormone “cortisol” can cause white adipose (fat) tissues to redistribute to the abdomen and increase a person’s appetite for energy-dense “comfort” foods.

Not getting enough sleep may be a risk factor for excessive weight gain.

Recommendations for sleep durations per day are:

  • 10–13 hours for children who are 3–5 years old, including naps
  • 9–12 hours for children who are 6–12 years old
  • 8–10 hours for adolescents who are 13–18 years old
  • 7 hours or more for adults who are 18–60 years old

A person may help improve sleep health by:

  • avoiding caffeine, large meals, and alcohol before going to bed
  • exercising during the day
  • ensuring the bedroom is quiet, relaxing, dark, and a comfortable temperature
  • avoiding looking at screens, such as TVs, computers, and smartphones, before sleeping and removing these devices from the bedroom if necessary
  • establishing a consistent sleep routine, going to bed at the same time each night and getting up at the same time each morning, even at weekends

People should aim to consult a healthcare professional yearly for a BMI check. They will be able to provide advice if someone wants to make changes to their diet and lifestyle or if they are trying to maintain a moderate weight.

A doctor can also advise someone if they think any lifestyle changes or other treatments, such as weight loss medications, are necessary.

A person should speak with a doctor if they are planning to lose weight to make sure they are doing so safely.

Obesity occurs when unusual or excessive levels of fat accumulate, which may cause health risks.

People may help prevent obesity by making certain lifestyle choices. For example, following a healthy, balanced diet, managing stress, and participating in regular physical activity.

It is best for a person to speak with a doctor if they are planning to lose weight to ensure they do so safely.