To gain weight, you need to eat more calories than your body burns each day. For most adults, that means adding 300 to 500 extra calories on top of your maintenance level, which typically puts total intake somewhere between 2,200 and 3,200 calories depending on your size, sex, and activity level. The exact number is personal, but calculating it takes just a few steps.
How to Find Your Maintenance Calories
Your body burns calories through three main channels: your resting metabolic rate (the energy it takes just to keep you alive), the calories you burn through movement and exercise, and the energy used to digest food. That last one, sometimes called the thermic effect of food, accounts for roughly 10% of your daily burn. Together, these three make up your total daily energy expenditure, or TDEE. That’s the number you need to eat above.
The simplest way to estimate your TDEE is to start with your resting metabolic rate and multiply it by an activity factor. Many online calculators do this automatically, but the activity multipliers look like this:
- Sedentary (desk job, little exercise): multiply by 1.2
- Somewhat active (light exercise 1–2 days/week): multiply by 1.3
- Moderately active (exercise 3–4 days/week): multiply by 1.4–1.5
- Very active (hard exercise 5+ days/week): multiply by 1.6–1.7
For example, a moderately active 30-year-old man with a resting metabolic rate around 1,800 calories would multiply by 1.5, giving a TDEE of roughly 2,700 calories. That’s the amount he’d eat to stay the same weight. To gain, he needs to eat more than that.
How Big Your Surplus Should Be
A surplus of 10–20% above your TDEE is the range most experts recommend. For someone maintaining at 2,700 calories, that works out to an extra 270 to 540 calories per day, bringing daily intake to roughly 2,970 to 3,240 calories.
That range matters because it controls how much of your weight gain is muscle versus fat. A moderate surplus of 300 to 500 calories supports a healthy gain of about 0.25–0.5% of your body weight per week. For a 150-pound person, that’s roughly 0.4 to 0.75 pounds per week. It sounds slow, but this pace lets your body actually build tissue rather than just store excess energy as fat.
If you’re new to strength training (less than six months of consistent lifting), your body can build muscle faster, so aiming for the higher end of the surplus makes sense. If you’ve been training for years, sticking closer to the lower end helps keep fat gain in check. Your body has a ceiling for how much muscle protein it can build in a given day, and eating far beyond that limit won’t speed up muscle growth. The extra calories just get stored as fat.
Protein and the Rest of Your Diet
Calories get you into a surplus, but protein is what actually builds the new tissue. The current consensus among sports nutrition researchers is to aim for 1.6 to 2.2 grams of protein per kilogram of body weight each day. For a 170-pound (77 kg) person, that’s about 123 to 170 grams of protein daily. Spreading that across three to four meals tends to work better than cramming it into one or two sittings.
Beyond protein, fill the remaining calories with a mix of carbohydrates and fats from whole foods. Carbs fuel your workouts and help with recovery. Fats support hormone production and make food taste good, which matters when you’re trying to eat more. There’s no need to obsess over exact ratios. Hit your protein target, eat enough total calories, and let carbs and fats fill in the rest based on what you enjoy eating.
High-Calorie Foods That Make It Easier
Eating in a surplus can feel like a chore if you’re filling up on salads and lean chicken breast. Energy-dense foods pack more calories into smaller volumes, making it much easier to hit your target without feeling stuffed. Good options include nuts and nut butters, olive oil, avocados, fatty fish like salmon and tuna, dried fruit, seeds, cheese, and whole grains. Adding a tablespoon of olive oil to vegetables or spreading peanut butter on toast are simple ways to add 100 to 200 calories without changing the size of your meal.
Some practical meal and snack ideas with their approximate calorie counts:
- Smoothie with Greek yogurt, banana, milk, whey protein, and peanut butter: ~540 calories
- Bagel with cream cheese and jelly: ~580 calories
- Oatmeal made with milk, honey, banana, and raisins: ~460 calories
- Turkey sandwich with avocado and mayonnaise: ~555 calories
- Trail mix with almonds, walnuts, raisins, and cereal: ~370 calories
- Peanut butter and jelly sandwich on whole wheat bread: ~400 calories
Even one or two of these added to your current diet can close the gap between maintenance and surplus.
What to Do if You Struggle With Appetite
Some people find it genuinely hard to eat enough. If that’s you, a few strategies can help. First, shift to eating five or six smaller meals instead of three large ones. A 500-calorie meal feels much more manageable than trying to eat 800 or 900 calories in one sitting.
Liquid calories are one of the most effective tools for people with small appetites. Smoothies, shakes, and even milk between meals add significant calories without making you feel as full as solid food would. A simple shake with milk, protein powder, banana, and peanut butter can deliver over 500 calories and goes down in a few minutes. Avoid filling up on water, diet soda, or other low-calorie drinks before or during meals, since they take up stomach space without contributing calories.
Adding calorie-dense toppings to meals you’re already eating is another low-effort strategy. Stir dry milk powder into soups, mashed potatoes, or oatmeal for extra protein and calories. Sprinkle cheese on eggs, drizzle olive oil over pasta, or toss chia seeds into yogurt. These small additions can easily contribute an extra 200 to 300 calories across the day without requiring you to eat a whole additional meal. Planning your eating times also helps. You may need to eat on a schedule rather than waiting until hunger shows up, especially in the early weeks before your appetite adjusts.
Tracking Progress and Adjusting
Weigh yourself at the same time each day (mornings work best) and look at the weekly average rather than any single day. Daily weight fluctuates based on water, sodium, and digestion, so the weekly trend is what matters. If you’re gaining 0.25–0.5% of your body weight per week, you’re on track.
If the scale isn’t moving after two to three weeks of consistent eating, you likely need to increase your intake by another 100 to 200 calories. Your body adapts to higher calorie intake over time. As you gain weight, your resting metabolic rate increases because there’s simply more of you to maintain. Non-exercise movement can also tick upward as your energy levels rise, meaning you burn more throughout the day without realizing it. These adaptations are normal and just mean you’ll need to periodically reassess and bump calories up.
Strength training alongside your surplus is what steers the extra calories toward muscle rather than fat. Without resistance exercise, a caloric surplus still produces weight gain, but a larger proportion of that gain will be body fat. Even two to three sessions per week of progressive resistance training makes a meaningful difference in body composition.