What's a good way to gain weight if you're underweight?

Answer From Katherine Zeratsky, R.D., L.D.

Eating nutritious foods that are high in calories is a good way to gain weight. It's also important to understand the reason why you're underweight.

Being underweight can be defined in a couple of ways. It can mean low weight for a person's height, defined as a body mass index (BMI) of less than 18.5. It also could be weight that is 15 to 20% below the typical weight for a person's age.

There are many reasons you may not be at your goal weight. Recovering from an illness or losing weight as you age are two examples. It's also common for athletes to want to gain weight as muscle.

It is best to see your health care provider if you lost weight unexpectedly. Your provider or a dietitian can help you gain weight in a healthy way. Together, you can create a plan based on your needs.

In general, your plan may include:

  • Eating more frequently. Slowly begin to eat 5 to 6 smaller meals during the day. Try to tune into your body to recognize when you might be hungry. But you may need to plan times to eat even if you aren't that hungry.
  • Choosing food with lots of nutrients. Set up a routine to eat and drink things you like and that have a lot of nutrients as well as calories. Talk with your health care provider or dietitian about how many calories to eat a day or in each meal. You also can ask how many servings you should eat of the different food groups.
  • Top it off. Add extras to your dishes for more calories, such as cheese in casseroles or nut butter on whole-grain toast. You also can add dry milk or liquid milk to foods for extra protein and calories. Some examples are mashed potatoes or soups.
  • Try smoothies and shakes. Avoid beverages with few nutrients or calories, such as diet soda. But a blend of high-calorie, nutritious ingredients in a smoothie or shake can help if you're eating on the go. Meal replacement drinks also may be part of your weight-gain effort.
  • But watch what and when you drink. Beverages can make you feel full. If that's the case for you, avoid drinking during a meal or before. But make sure you are drinking enough throughout the day.
  • Exercise. Exercise, especially strength training, can help you gain weight by building up your muscles. Exercise also may stimulate your appetite.

There also are medicines that help boost the feeling of hunger.

From Mayo Clinic to your inbox

Sign up for free, and stay up to date on research advancements, health tips and current health topics, like COVID-19, plus expertise on managing health.

To provide you with the most relevant and helpful information, and understand which information is beneficial, we may combine your email and website usage information with other information we have about you. If you are a Mayo Clinic patient, this could include protected health information. If we combine this information with your protected health information, we will treat all of that information as protected health information and will only use or disclose that information as set forth in our notice of privacy practices. You may opt-out of email communications at any time by clicking on the unsubscribe link in the e-mail.

Jan. 11, 2023 See more Expert Answers

See also

  1. Added sugar
  2. Alcohol use
  3. Alkaline water
  4. Are energy drinks bull?
  5. Artificial sweeteners and other sugar substitutes
  6. Autism spectrum disorder and digestive symptoms
  7. Bad food habits at work? Get back on track in 5 steps
  8. Best oil for cooking?
  9. Dietary guidelines
  10. Breastfeeding nutrition: Tips for moms
  11. Caffeine: How much is too much?
  12. Is caffeine dehydrating?
  13. Calorie calculator
  14. Can whole-grain foods lower blood pressure?
  15. Carbohydrates
  16. Chart of high-fiber foods
  17. Cholesterol: Top foods to improve your numbers
  18. Coconut water: Is it super hydrating?
  19. Coffee and health
  20. Diet soda: How much is too much?
  21. Dietary fats
  22. Dietary fiber
  23. Prickly pear cactus
  24. Does soy really affect breast cancer risk?
  25. Don't get tricked by these 3 heart-health myths
  26. Don't go cuckoo for coconut water
  27. Eat more of these key nutrients
  28. Eggs: Bad for cholesterol?
  29. Fiber: Soluble or insoluble?
  30. Fit more fiber into your diet
  31. Get to know the new Nutrition Facts label
  32. Healthy-eating tip: Don't forget fiber
  33. Hidden sources of sodium
  34. High-protein diets
  35. How to track saturated fat
  36. Is there more to hydration than water?
  37. Juicing is no substitute for whole foods
  38. Juicing
  39. Limit bad fats, one step at a time
  40. Make food labels required reading
  41. Monosodium glutamate (MSG)
  42. Need a snack? Go nuts!
  43. Need more fiber? Take 3 steps
  44. Nutrition rules that will fuel your workout
  45. Nuts and your heart: Eating nuts for heart health
  46. Omega-3 in fish
  47. Omega-6 fatty acids
  48. Phenylalanine
  49. Protein: Heart-healthy sources
  50. Health foods
  51. Portion control
  52. Planning healthy meals
  53. High-fiber diet
  54. Sodium
  55. Step away from the saltshaker
  56. Taurine in energy drinks
  57. Time to cut back on caffeine?
  58. Trans fat
  59. Daily water requirement
  60. What's considered moderate alcohol use?
  61. What's the difference between juicing and blending?
  62. Working out? Remember to drink up
  63. Yerba mate