Sustainable weight management involves making changes you can maintain over a long period. It aims to improve your overall health instead of encouraging fast and temporary weight loss or gain.

Whether your goal is to gain or lose weight, it’s almost always best to pick a strategy that allows you to sustain your weight long term. Often, this means making changes to your lifestyle habits rather than following extreme diets or workout programs for a short time.

Losing or gaining weight too quickly can cause health complications, but following a gradual program often improves your overall health. No matter what your goal is, you can take several steps to achieve it, such as:

  • making a commitment, like writing down your goal
  • evaluating where you are now and where you need to be
  • setting a realistic weight loss or weight gain goal
  • identifying family, friends, or other people who can support these goals
  • monitoring your progress regularly

Healthcare professionals often use the body mass index (BMI) to determine whether you’re above or below a healthy weight for your height. The formula for adults is one of these two:

  • weight (kg) / [height (m)]2
  • weight (lb) / [height (in)]2 x 703

Here’s how you can calculate BMI using the metric system:

StepExample
Take your weight in pounds and divide it by 2.2 to get kilograms. Divide your weight in kilograms by your height in meters, and then do it again.
Find your height in meters by taking your height in inches, multiplying by 2.54, and dividing by 100.5’4” = 64 inches
64 * 2.54 ÷ 100 = 1.63
Divide your weight in kilograms by your height in meters and then do it again.75 kg ÷ 1.63 ÷ 1.63 = 28.2

Once you know your BMI, you can compare it to the following table:

Score (kg/m2)Description
under 16.5severely underweight
under 18.5underweight
18.5 to 24.9acceptable weight
25 to 29.9overweight
over 30obesity

Researchers have found that these cutoffs underestimate obesity in people from Asia and South Asia, so they created new cutoffs for these groups:

Score (kg/m2)Description
23 to 24.9overweight
over 25obesity

The BMI scale is not perfect, though. It only considers height and weight, and not your body composition or health status.

The formula was originally calculated on the height and weight of European males, so it does not fully factor in differences related to sex and race or ethnicity.

Some people, such as athletes with larger amounts of muscle, might also have a BMI in the overweight range despite having low body fat percentages.

BMI should be considered alongside the results of other tests that measure important aspects of your health, such as:

Body fat percentage, waist circumference, and waist-to-hip ratio may also help determine your health status and the weight range that’s appropriate for your age and needs.

Learn more about determining what’s considered a healthy weight.

If your goal is to lose weight, you’ll need to eat fewer calories than your body burns. If you want to gain weight, you’ll need to eat more calories. If you need to stay at your weight, you need to balance caloric input and output.

Weight loss

Health experts recommend a calorie deficit of about 500 to 750 calories per day for sustainable weight loss.

You may find it helpful to record your food intake over several days to get an idea of how many calories you typically consume in a day.

If your weight has been stable recently, cutting 500 calories a day off your diet may lead to roughly a pound of weight loss per week.

This estimation comes from knowing that a pound of fat contains 3,500 calories worth of energy. So, 500 fewer calories per day for 7 days (500 x 7 = 3,500) may result in losing 1 pound. This is sometimes referred to as the “3,500 calorie rule.”

However, keep in mind that this rule tends to overestimate weight loss.

Your metabolism usually slows down after long periods of undereating because your body is protecting itself from starvation. This is known as metabolic compensation.

In other words, if you start eating fewer calories, or cut too many calories per day, your body will want to conserve energy (fat) or use it more efficiently, which means you may not lose weight.

When trying to lose weight sustainably, consider avoiding:

  • weight loss cleanses and detoxes
  • extreme calorie restriction (more than 500 calories per day)
  • weight loss supplements and over-the-counter medications, unless recommended by a doctor (particularly those that contain banned ingredients, like ephedrine)

A good nutritional strategy for losing weight is to look for sources of empty calories in your diet and replace them with healthier alternatives. Empty-calorie foods are those high in calories without any nutritional value.

Examples of possible empty calories include:

  • alcohol
  • products with added sugars
  • sugary beverages, such as:
    • soda
    • sports drinks
    • fruit drinks
  • fast food
  • candy
  • ultra-processed foods

Weight gain

Some experts recommend increasing calories by 10% to 20% over the maintenance requirement when trying to gain weight.

If your goal is to gain muscle, it’s important to consume plenty of high protein foods while focusing on a balanced overall diet to make sure you’re getting enough nutrients. Regularly lifting weights is also essential to avoid body fat gain.

Strategies best to avoid when trying to gain muscle include:

  • using anabolic steroids
  • dirty bulking” where you eat junk food to gain weight quickly
  • following fad diets promoted by celebrities without checking with a healthcare professional
  • adding more than about 500 extra calories to your diet per day
  • eating too many empty calories

You may want to develop exercise habits you can sustain over time when you’re trying to lose weight. When you see rapid weight loss over a few days, it often means you’re losing fluid.

The opposite is true when trying to gain weight. As your body starts storing more carbohydrates in your muscles, it also stores more water. Each gram of carbohydrates stored in a muscle contains at least 3 grams of water.

Engaging in regular aerobic exercise in your weekly routine can help with weight loss goals and overall fitness.

Many types of aerobic exercise can help you lose weight, but it’s important to choose those you enjoy, or you may find it hard to stick with them in the long term.

Some ideas of aerobic exercise include:

  • running
  • biking
  • jogging
  • swimming
  • rowing
  • skating
  • mountain climbing
  • circuits
  • jump rope
  • dancing

If your goal is to gain weight and lean muscle, adding resistance training to your weekly exercise routine is a must.

Resistance training may involve lifting free weights, but it can also include:

  • bodyweight exercises
  • calisthenics
  • rock climbing
  • weight machines
  • resistance band exercises
  • medicine balls or sandbags

Chronic stress may increase your cortisol levels, which can lead to unwanted effects, such as making you more prone to overeating, gaining weight, and having difficulty building lean muscle.

Stress management activities may vary from person to person. The activities you choose don’t matter as much as the way these activities make you feel.

Some options to consider include:

If your efforts have yielded no results or if you’ve experienced a weight-related challenge, you may want to seek help from a healthcare professional.

Working with a professional may help you develop a comprehensive plan with measurable strategies.

Some professionals you may want to work with on your weight management goals include:

  • personal trainers with certifications like ACE, ACSM, or NASM
  • registered dietitians or nutritionists
  • sports-specific coaches
  • dance or other instructors for particular activities
  • mental health professionals

Each body is different and may respond to weight management efforts in a different way. What’s a healthy weight for you might not be a healthy weight for another person, and what gets you there may be different from what works for someone else.

Your BMI can be a starting point to evaluate how much you should weigh for optimal health, but even this formula doesn’t consider factors such as your body composition and individual genetic factors.

In general, it’s best to follow a dietary and exercise plan that allows you to lose or gain weight gradually. Trying to change your weight quickly may negatively impact your health or cause you to be disappointed if your goal isn’t realistic or sustainable.

Working with a healthcare professional may provide insight into more strategies that improve your overall fitness and health status.