How To Gain Weight Safely

It occurs more often than you might think: A doctor asks you to gain weight, or asks you to help your child add some extra pounds. It can happen because you:

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Have underweight (a BMI under 18.5 for adults or in the 5th percentile for children)
Are recovering from surgery, severe illness or hospitalization
Have a chronic illness that’s causing weight loss
Are receiving treatment for an eating disorder
Need to build strength heading into a medical procedure or therapy

Most of us have a basic understanding of how to gain weight. But how to gain weight fast, without damaging your health? That can be a bit more challenging.

Pediatrician and adolescent medicine specialist Ellen Rome, MD, and registered dietitian Devon Peart, RD, MHSc, explain how to gain weight safely at any age.

How to gain weight

When you think about a weight gain diet, do you picture plates piled high with fast food and sugary snacks? That could certainly add weight, but it won’t do your health any favors.

It’s possible to gain weight in a nutritious, sustainable way. And it’s not as difficult as you might think. Here’s what to do.

8 foods that can help you gain weight safely

Increase your daily calories and protein

To gain weight, you need to consume more calories than you burn in a day. Many people can do that by increasing their daily intake by 300 to 500 calories. But your target could be higher or lower based on:

Your age and sex
Your body composition and activity level
The reason you need to gain weight
Your nutritional goals
Your metabolic and digestive health
The medications you take, if any

“Everybody’s different,” Peart says. “Ask your doctor or dietitian what a healthy target looks like for you.”

Upping your protein intake is also a critical part of a healthy weight gain eating plan.

How much you need depends on many of the same factors that determine your ideal calorie surplus. But generally speaking, it’s good to shoot for between 1.2 and 2 grams of protein for every kilogram (kg) of body weight.

So, if you weigh 100 pounds (45.5 kg), you should try to eat between 54.6 and 91 grams of protein a day. But keep in mind: More is not necessarily better. Taking in too much protein can stress your kidneys.

“If you’re frequently eating more than 1.2 to 2 grams of protein per kilogram of body weight, consider asking your provider to run a blood test to check your kidney function," Dr. Rome adds.

Choose nutritious, calorie-dense foods

When you’re trying to gain weight, you need to think about both the quantity and the quality of the calories you take in. Your goal is to strike the right balance of proteins, fats and carbs. These nutrients fuel your body and keep you healthy.

Avoid filling up on low-calorie foods, like popcorn, that don’t offer much in the way of nutrients. Instead, Peart says to turn to foods that are rich in heart-healthy fats, like:

Avocados
Nuts and nut butters
Olives

You can also try nutritious, calorie-dense options, such as:

Cheese
Unsweetened dried fruit

“These foods help bring more calories to your meals or snacks,” she notes. “Adding avocado, cheese and dried fruit to your salad is a great way to add extra calories without sacrificing your nutrition goals.”

Increasing your child’s daily calories

Dealing with a pint-sized picky eater? Strategies worth trying include:

Spicing up snack time: Dr. Rome says guacamole, hummus and bean dips are great sources of healthy fats that kids and teens often enjoy as snacks.
Getting creative: Add nutritional yeast to your kid’s mac and cheese, stir extra olive oil into their soup and incorporate wheat germ into their favorite baked treats.
Making substitutions: Cook your kiddo’s oatmeal in your milk of choice, instead of water. Use black beans instead of flour to punch up the protein in homemade brownies. Spread mashed avocado on sandwiches or toast instead of mustard or other low-calorie spreads.

Dr. Rome adds that it’s also OK for kids to indulge in some ice cream — in moderation.

Eat frequently

You want to walk away from your meals feeling satisfied, not stuffed. That’s why Peart recommends eating smaller, more frequent meals and snacks throughout the day. Aim to eat something every two to three hours.

“This can be helpful if you have a smaller appetite or a health condition that makes it hard to eat enough during breakfast, lunch and dinner,” she reports.

Get moving

Peart points out that being too sedentary can dampen your appetite. She recommends going for a walk or trying another type of light movement to stimulate hunger.

Try smoothies and protein shakes

Smoothies and protein shakes can be a great addition to a weight gain eating style. They’re especially helpful for those with smaller appetites.

“For some, drinking may be more palatable (or easier to consume) than solid food, so that’s one way to get those calories,” Peart notes. “And you can add ingredients like honey or maple syrup, fruit, higher-fat Greek yogurt and even dry oats.”

For kids, Dr. Rome recommends steering clear of powders in favor of the pre-mixed shakes you can buy off the shelf.

“They pack a lot of calories into a container the size of a juice box, and it’s perfect for a parent to prep the night before and give to a child in the morning for breakfast,” she says.

Avoid drinks before dinner

Avoid drinking large amounts of liquid before a meal.

“Drinking before a meal fills your stomach up,” Peart explains. “That could leave you less hungry come mealtime. Drinking after or in between meals, not right before, can help you avoid spoiling your appetite.”

Dr. Rome says temperature matters, too: “Cold foods and beverages are less filling than hot foods, so you can opt for cold foods when you or your child needs to eat more.”

Build muscle

Gaining weight isn’t just about adding fat. You also want to build muscle. Weightlifting and other strength-building exercises can help you do that.

Training each major muscle group twice a week is typically a good place to start. But check with your provider to be sure it’ll work for you.

“Always consult with your provider before starting a new exercise regimen,” Dr. Rome advises. “They can help you create a workout plan that’s safe, sustainable and aligned with your weight gain goals.”

How quickly can weight be put on?

How fast is too fast when it comes to healthy weight gain? And how slow is too slow?

Our bodies react to food in different ways, so the best person to answer that question is your provider. Still, there are some general guidelines that are worth keeping in mind:

For children: “For kids who aren’t in the hospital receiving nutritional support, we hope to see a gain somewhere between a half pound and two pounds each week,” Dr. Rome says.
For adults: Peart says that for most adults, adding about 500 extra calories a day to their diet will lead to a gain of about a pound or more a week.

If you aren’t gaining weight — or aren’t gaining it as fast as your provider expected — let them know. Ditto if you’re losing weight. They may need to adjust your eating plan, run tests or try another approach.

To get the best results, it’s critical that your weight gain plan is developed with the support and supervision of your care team. And whenever possible, that care team should include a registered dietitian.

“A dietitian can create a plan tailored to you and your needs,” Peart emphasizes. “They can work with you and your likes, dislikes and appetite size to ensure you reach your goals in a healthy way.”