How to gain healthy weight fast

Weight loss attracts a lot of media attention and research. But plenty of people want to know how to gain weight, not lose it. Maybe you may want to gain weight (along with muscle) to change your physique. Or perhaps you’ve lost weight due to aging or health problems, and you want to safely boost your body mass index (BMI).

Whatever your reason, healthy weight gain is possible. 

If you want to gain weight, you must maintain a “positive energy balance.” That means your calorie intake must be greater than the number of calories you burn (Iraki, 2019). This is also known as overfeeding (Leaf, 2017). 

The number of calories you need to eat and drink to achieve this positive energy balance will depend on your age, health status, activity levels, and other factors. For example, if you exercise all the time, you’ll probably need to eat a high-calorie diet to add weight (Iraki, 2019).

To figure out how many calories you need to eat each day to get to your desired weight, use this free online bodyweight planner from the U.S. National Institutes of Health. It will help you estimate your daily calorie targets based on your current health information, your desired weight, and the date you hope to achieve that weight.

Just keep in mind that if you’re starting a new workout program and at the same time trying to gain weight, you may need to eat even more calories. That’s because you’ll burn some extra calories during exercise.  

If all you care about is gaining weight as quickly as possible, you just need to eat more and move less. One study of young men (average age 21) found that adding 1,000 extra calories to their daily diet while limiting their physical activity caused them to gain an average of 18 pounds in 100 days (Leaf, 2017).

More research has found that gentler overfeeding leads to more gradual weight gain. For example, if you want to gain 15 pounds during the coming year, researchers have found that you can do this by maintaining your current workout habits while adding between 200 and 330 extra calories to your daily total (MacEwan, 2016).

But if you want to add weight in a healthy way, you’ll have to be more careful about the foods you eat. 

If you want to gain healthy weight, you need to eat nutritious foods. (More on those below.) Even if you’re underweight and a doctor has told you to gain weight for your health, doing so by only eating processed snack foods is risky. 

A registered dietitian can help you put together a healthy, customized plan. But if you want to go it alone, start by using that NIH calculator to estimate your daily energy needs. 

Keep in mind that gaining weight gradually may be healthier than adding it quickly. Research has found that aiming to add between half a pound and a pound of weight each week may be safer and healthier than adding weight more rapidly (Iraki, 2019). 

Keeping a diary of what you eat each day—and keeping a close eye on your scale—can help you gauge whether you’re gaining weight too quickly. To get a good sense of how your weight is changing, try always to weigh yourself at the same time of day and in the same clothing. 

For example, you could weigh yourself first thing in the morning wearing only your underwear or pajamas (Pacanowski, 2015; Cleveland Clinic, 2019).  

When mapping out any diet, it’s helpful to think of foods based on their “macros” or macronutrient components. These include proteins, carbohydrates, and fats. 

Countless research papers and books have explored the ideal macronutrient balances for a “healthy diet.” Right now, experts still can’t agree on just what that sort of diet looks like. 

That said, health authorities have identified good daily macronutrient targets based on a person’s age, sex, size, and activity levels. To find out what those levels are for you, use this free online calculator from the U.S. Department of Agriculture (USDA). 

Once you have those protein, fat, and carbohydrate targets, you can use them to design a diet of healthy foods that allows you to add calories while getting all the nutrients your body needs.

Some examples of healthy, protein-rich foods include (Bradlee, 2017):

• Lean meats such as beef, lamb, and pork

• Poultry (chicken breast, turkey) 

• Fish

• Dairy (milk, yogurt, cheese)

• Legumes (beans and peanuts), soy, nuts, and seeds

• Eggs

• Protein powders and supplements

Examples of healthy carb-rich foods are (Englyst, 2007):

• Fruits

• Vegetables

• Starchy vegetables such as sweet potatoes

• Whole-grain foods such as quinoa or brown rice

Some examples of healthy fats are (Liu, 2017):

• Olive oil 

• Avocado

• Nuts and seeds 

• Fatty fish (such as salmon, herring, mackerel, and sardines)

• Peanut butter and nut butters

• Full-fat dairy products (such as cheese, whole milk, butter, and Greek yogurt) 

What to avoid when trying to gain weight

One of the most important rules of healthy eating is to avoid, as much as possible, packaged or heavily processed foods. That means limiting your intake of crackers, chips, desserts, soft drinks, and other junk foods. Again and again, studies tie these foods to problematic weight gain and poor health outcomes. On the other hand, minimally processed whole foods are almost inherently good for you (Monteiro, 2009).

If you want to add muscle mass and weight, you’ll need to eat enough calories. You’ll also need to train. There are almost endless ways to combine different workout plans and diets to get bigger and stronger. But research on bodybuilders suggests that some strength training and dieting approaches are more effective than others (Schoenfeld, 2019). 

How to train for bigger muscles

Your goal is to train a diverse group of muscles using various resistance exercises or movements. This includes dumbbells or other “free weights,” strength-training machines, or body-weight exercises such as pushups and pull-ups. 

Training “intensity” refers to the number of repetitions (reps) you can complete before muscle failure prevents you from doing more with proper form. Low intensity is usually defined as 1-5 reps, moderate intensity is 6-12 reps, and high intensity is anything above 12 reps. Research has found that moderate intensity may be best for strength and muscle gains (Schoenfeld, 2010). 

Of course, training volume also matters. While it’s important to give your muscles at least a day or two of rest between workouts, training more is going to promote greater muscle growth than training less (Schoenfeld, 2010). 

Nutrition for weight and muscle gain

If you want to gain weight while adding muscle, your diet should pretty closely match the one detailed above. Again, you can use the NIH and USDA calculators to identify your daily calorie and macronutrient targets. 

The one big difference here is that you’ll want to eat more protein. The cells and tissues of your muscles are made up of protein amino acids. Your body can make some of these amino acids by itself. But others, known as “essential” amino acids, have to come from your diet. You need these protein building blocks if you want to add muscle (Wolfe, 2017). 

For bodybuilders, the goal should be to eat roughly 1.6 to 2.2 grams of protein per kilogram of body weight (g/kg/day). That means if you weigh 180 pounds (approx. 82 kg), your daily protein intake should land somewhere between 131-180 g. You also want to spread your protein intake throughout the day. Research suggests that this approach to protein intake is best if you want to build both size and muscle. If you’re struggling to hit your daily protein goals, whey protein smoothies or supplements can help you get there (Schoenfeld, 2018; Iraki, 2019).

There are right and wrong ways to add weight. By eating the right foods, taking things slow, and optimizing your workout routines, you should be able to add weight and muscle safely.

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Current version

September 20, 2021

Written by

Health Guide Team

Fact checked by

Felix Gussone, MD

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About the medical reviewer

Felix Gussone, MD, Ro

Felix Gussone is a physician, health journalist and a Manager, Medical Content & Education at Ro.