Calorie Surplus: Gain Weight and Build Muscle

Whether your goal is to gain weight or build muscle, you’ve probably been told or have read that you need to be in a calorie surplus.

But you may be left wondering what exactly a calorie surplus is or how much of one you need to meet your weight gain or muscle-building goals.

This article explains everything you need to know about a calorie surplus, including what it is, how much of one you need to gain weight or build muscle, and which foods you should eat to create one.

What is a calorie surplus?

A calorie surplus is any number of calories over the number of calories that you need to maintain your body weight.

You can think of your body weight as a teeter-totter.

On the left side, you have energy or calorie intake, and on the right side, you have calorie expenditure or output.

Calorie intake is the total number of calories you get from food and beverages each day.

Calorie output is the total number of calories you burn or expend each day.

Three components comprise calorie output (1):

• Resting energy expenditure (REE): This is the number of calories you burn at rest. REE is the largest component of calorie output, comprising 60–70%.
• Thermic effect of food (TEF): This is the number of calories you use to digest and process food. Protein requires the most energy to digest and process, followed by carbs and fats.
• Activity energy expenditure (AEE): This is the number of calories you use during sports-like exercise and nonexercise activities like mowing the yard or walking the dog.

When the teeter-totter is flat or in balance — meaning the number of calories you consume (calorie intake) equals the number of calories you burn (calorie output) — your body weight stays the same.

In this case, the number of calories you consume to maintain your weight is known as your maintenance calories.

But, if you consume fewer calories than what you expend, the left side (energy intake) goes up while the right side (energy output) goes down.

This means you’re in a calorie deficit and you’ll lose weight.

Conversely, if you consume more calories than what you expend, the left side goes down while the right side goes up.

In this case, you’re in a calorie surplus, and you’ll gain weight.

Some days you may be in a calorie deficit and other days in a calorie surplus.

But rarely — if ever — do humans eat the exact number of calories they expend each day.

Therefore, what matters most for your body weight is which side of the teeter-totter you’re most frequently on.

How much of a calorie surplus do you need?

The recommendation that you need to be in a calorie surplus to gain weight or muscle isn’t very helpful.

How do you know the number of calories you should eat to be in a calorie surplus?

How large should the calorie surplus be to gain weight or build muscle?

Recall that there are three primary components of energy expenditure.

These components are influenced by several factors, including age, health status, body composition, gender, and activity level, among other factors.

It’s these factors that influence your maintenance calories and therefore the number of calories you need to gain weight.

You don’t need to know your maintenance calories to gain weight but it’s very helpful.

The first step to determine the number of calories you should eat to gain weight is to estimate your maintenance calories.

There are several online calculators like this one that can help you do this.

Or, for a rough estimate, you can multiply your body weight in pounds by 14 if you’re a female or 17 if you’re a male.

This translates to 2,100 for a 150-pound (68-kg) female, and 2,550 for a 150-pound male.

This estimate assumes light activity so you may need more or fewer calories depending on your activity level as well as your age and body size.

Once you know your maintenance calories, add 200 to 500 to determine your calorie goal for weight gain (2, 3).

In the earlier example, this would equate to 2,300 to 2,600 for a female and 2,750 to 3,050 for a male.

Even if you’re goal isn’t to build muscle, lifting weights can help ensure that most of the weight you gain is in the form of muscle rather than fat.

If you’re skinny, have a fast metabolism, or need to put weight on fast, aim for the higher end of the 200–500 calorie surplus range, whereas if are muscular and advanced with training, aim for the lower end of the range.

This calorie surplus range should allow you to gain 0.25 to 0.5% of your body weight each week, or 0.4 to 0.8 pounds (0.2 to 0.4 kg) per week for a 150-pound person.

If you’re gaining weight at a faster rate, you may need to decrease your calories.

Just as losing weight too quickly can be harmful so too can gaining weight too quickly.

As you begin to gain weight, you’ll need to recalculate your calorie goals at least every 4 to 6 weeks until you meet your desired weight.

This is because the more you weigh, the higher your calorie needs will be.

Foods to help you create a calorie surplus

While there is no single best food for weight gain, some foods are better than others.

Foods rich in fat are especially helpful since fat provides more than double the calories of carbs or protein.

Here are some healthy foods rich in fat to help you gain weight:

• avocados
• whole eggs
• oily fish like salmon, herring, mackerel, or tuna
• nuts and seeds like almonds, chia seeds, flaxseeds, pecans, sunflower seeds, and walnuts
• nut butter like peanut or almond butter
• full-fat cottage cheese, milk, and yogurt

Limit fatty foods like processed meats, bakery items, and fried foods.

If you cannot tolerate fat well, here is a list of high calorie, low fat foods to eat.

High calorie shakes and smoothies can also help you gain weight since you can load them with calories.

You can even add protein powders and weight or mass gainer supplements to your shakes and smoothies for extra protein and calories.

Liquid calories tend to make you less full than solid calories, so shakes and smoothies can be especially beneficial if you struggle with a poor appetite.

If you have a poor appetite, try these natural appetite stimulants.

Meal replacements can be useful for weight gain if you use them as a high calorie snack between meals rather than to replace a meal.

And although many fruits and vegetables tend to be low calorie, there are plenty of higher calorie options.

Here is a list of high calorie fruits and high calorie vegetables to add to your diet.

The bottom line

To gain weight, you must eat in a calorie surplus, or a calorie level greater than the number of calories you need to maintain your weight.

A calorie surplus in the range of 200 to 500 calories daily should allow you to gain 0.4 to 0.8 pounds (0.2 to 0.4 kg) per week.

To reach and maintain a calorie surplus, focus on foods rich in fat, shakes and smoothies, weight gain supplements, and other high calorie foods, including fruits and vegetables.