When it comes to weight, most people want to lose it, not gain it. Yet there are many individuals who struggle to put weight on and keep up a strong, healthy physique. “Diet culture is so rampant in our society that we often fail to recognize that many people may have wellness goals unrelated to weight loss,” says Jennifer Mimkha, R.D, plant-based dietitian in West Chester, Pa, and founder or Prana Nutritionist.  

Why would you want to gain weight?

Numerous reasons might prompt individuals to need to gain weight or get stronger. Some women are trying to gain weight to support a healthy pregnancy, while others have lost too much weight on a diet or from illness, and are now trying to correct that situation, which can also trigger hormonal imbalances that stem from being underweight, Mimkha says. 

Athletes may need to gain muscle mass and strength and that means bulking up and adding weight, says Lindse Reynolds, a certified nutritionist based in Denver and manager of the wellness program for KOS the maker of plant-based energy products. 

One general rule of thumb to determine if you should gain weight? Check your body mass index (BMI), and if it’s under 18.5, that indicates you could be medically underweight, which can come with health woes. “Being underweight can mean you're in danger of lethargy, a compromised immune system, even osteoporosis,” Reynolds says. If you’re concerned about being underweight, talk with your doctor.   

How to gain weight the healthy way

So if you need to gain weight to be healthy, the question is: How to do it a healthy way? That's not just noshing on more calories, as many Hollywood A-listers do when they need to transform their bodies for a movie. Matthew McConnaughey is reported to have loaded up on beer, cheeseburgers, and pizza to add pounds for his 2016 role in Gold. No nutrition recommends this ad hoc "more calories is better" approach. The key is to eat healthy foods that stoke your lean body to build bulk and get stronger as you gain weight.

“Telling somebody to eat more isn’t only unhelpful but insensitive," says Mimkha. "It's similar to telling somebody who is overweight to just eat less. More calories will certainly help promote weight gain, but it’s rarely as simple as that.” 

Your metabolism, activity level, medical history, age, gender, gut health, and current diet can all be contributing factors as to why you're underweight in the first place, Mimkha says. If you’re not absorbing nutrients because of gut issues, for instance, gaining weight can prove to be difficult and you need medical guidance. She recommends working with a qualified nutritionist to make sure you’re gaining weight correctly and avoiding pitfalls or nutrient gaps.

Still, adding calories can be a good starting point, and to that end, Reynolds recommends adding 300 to 500 extra calories per day to start with. Just don’t add them all at once, as your body needs time to adapt to the extra energy. Because you’ll be eating more fiber, this may cause temporary gastrointestinal issues such as gas or bloating. By adding more food slowly, you’ll most likely bypass those adverse effects. 

Each week, turn up your calorie intake by100 calories a day for the first week. Then another 200 calories a day the next week, until you’re eating 300 to 500 extra calories a day. Increase serving sizes at meals or plan for an extra snack during the day, Reynolds says. 

Foods that help you gain weight

While you can easily add carb-heavy plant foods such as rice and beans to your plan, but some foods stand out as heavy-hitters that are as nutrient-dense as they are calorie-dense. Note that many of these contain high-fat content but since they are full of healthy fat, they won't raise your LDL or bad cholesterol, and in fact, studies show they may lower it.

Here are six to put on your radar: 

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1. Avocados

Guacamole fans should love seeing avocados on the list. Not only do avocados come with heart-healthy fats, but one large avocado has about 240 calories and 10 grams of fiber. Each avocado contains about 21 grams of monounsaturated and polyunsaturated fats, often called the "good fats" because eating them has been linked to lower levels of bad (LDL) cholesterol.

On Chef AJ’s Calorie Density Chart, which she uses to teach individuals how to lose weight, avocados are one of the foods that cross what weight loss expert Chef AJ calls the red line, essentially foods that will hinder weight loss, which means that if you want to gain weight, these should be fair game.

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2. Nuts and seeds

Nuts and seeds not only contain health-promoting polyunsaturated and monounsaturated fats but also calories, which is why many people avoid them. Nuts and seeds contain 2,800 calories per pound, which is why Reynolds recommends aiming for adding a handful or two of nuts and seeds a day. Weight-gain-friendly versions include cashews, flax seeds, pumpkin seeds, sunflower seeds, almonds, pecans, and walnuts. 

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3. Nut butter

\When trying to boost the number on the scale and do it without other health complications, nut butter can be a convenient and easy way to gain mass. Just make sure that you’re opting for varieties free of added sugar, oils, and preservatives, Reynolds says. Almond and Cashew butter is healthier than some others, including peanut butter, which can be mixed with sugars.

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4. Olives

Another source of heart-healthy fat, olives contain between 11 and 15 percent fat, depending on the type. Plus, a half-cup of ripe canned olives contain about 77 calories, and they’re packed with good-for-you nutrients like copper and iron, all of which make them a weight gain winner in Mimkha’s playbook.  Add them to soups, salads and any dish to give it more heart-healthy fat and fiber-filled calories.

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5. Protein powders

Make a morning smoothie and add any fruit or vegetable that you want, but Reynolds recommends also topping it off with some nut butter, full-fat coconut milk, and a plant-based protein. Plant-based protein powder can be made of pea protein, rice, and soy, all of which might be the secret in giving your smoothie extra benefit for moving the needle up on the scale. Protein powders, which pack in a healthy dose of nutrition, can be a simple way to boost the calorie count of those smoothies. There are numerous powders on the market; just check that you’re buying one that’s vegan. 

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6. Potatoes

To gain weight, this spud's for you! People who are trying to lose weight often eschew potatoes, but on the flip side, potatoes can be a good add to a weight gain plan, Reynolds says. Yet rather than choosing potato chips or French fries or loading baked potatoes with butter and sour cream, which are still unhealthy even if you’re opting for vegan versions, top a white or sweet potato with black beans and steamed veggies or banana, nut butter and some type of seed.