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Muscle & Strength

How to Gain Weight Healthily

2 min read · Sources listed below

Most health advice targets weight loss, leaving people who want to gain weight under-served. If you are underweight or a "hard gainer," here is how to add weight healthily - mostly as muscle, not just fat.

First, find your surplus

To gain weight you must eat more calories than you burn. Find your maintenance with the Calorie Calculator, then add about 300-500 kcal per day for a steady gain of roughly 0.25-0.5 kg per week. Going far higher just adds fat.

Eat enough protein

Protein builds the muscle, not just the weight. Aim for 1.6-2.2 g/kg per day - use the Protein Calculator. Set the rest of your intake with the Macro Calculator.

Choose calorie-dense whole foods

If you have a small appetite, large low-calorie meals are hard to finish. Lean on energy-dense, nutritious foods:

  • Nuts, nut butters, seeds, and olive oil
  • Whole milk, Greek yogurt, and cheese
  • Oats, rice, potatoes, and whole-grain bread
  • Eggs, fatty fish, chicken, and lean meats
  • Smoothies and shakes when solid food is hard to manage

Lift to gain muscle, not just fat

A calorie surplus without training adds mostly fat. Resistance training 3-4 times a week, with progressive overload, directs those extra calories toward muscle. Track your strength gains over time.

Tips for small appetites

  • Eat more frequently - add 2-3 snacks between meals.
  • Drink some of your calories with milk-based shakes; liquids fill you up less.
  • Do not fill up on water or low-calorie volume right before meals.
  • Be consistent - weight gain, like loss, shows up over weeks.

When to see a doctor

If you are losing weight unintentionally, or cannot gain despite eating well, see a doctor to rule out underlying causes such as thyroid problems, digestive conditions, or other illness.

Frequently Asked Questions

How many extra calories should I eat to gain weight?
About 300-500 kcal above maintenance per day for a steady, mostly-lean gain of roughly 0.25-0.5 kg per week.
How can I gain weight if I have no appetite?
Eat calorie-dense foods, add frequent snacks, drink milk-based shakes, and avoid filling up on water or low-calorie volume before meals.
Can I gain only muscle and no fat?
Some fat gain usually comes with muscle gain in a surplus. Keeping the surplus modest and training hard maximizes the muscle portion.

Tools for training and nutrition

Evidence note: The training and protein guidance in this article was checked against the references below. This site is not a medical provider and the content is not personal medical advice. Report an error at [email protected].

Sources: MedlinePlus: Weight Control · MedlinePlus: Dietary Proteins