Last updated: March 2025
The best way to gain weight healthily is to gradually add around 300 to 500 extra calories per day from nutrient-dense foods while eating 5 to 6 smaller meals and incorporating strength training to build muscle rather than fat. You want to be patient with this. In our experience coaching individuals, we've seen people try to double their portions overnight and give up within a week. Slow and steady really does win here.
Before you start, you need a plan. Not a complicated one. You need staple foods you can keep around even when you don't feel like cooking. Think peanut butter, cheese, eggs, whole milk, yogurt, nuts, seeds, avocados, beans, lean meats, and starchy veggies like potatoes. You should choose from a variety of food groups: fruits and vegetables, starchy carbs, dairy and alternatives, and protein sources like beans, pulses, fish, eggs, and lean meat. You also need the right mindset. This isn't a license to eat whatever you want. The key to healthy weight gain is to pick nutrient-rich foods as often as possible. Empty-calorie stuff like soft drinks, chips, and candy will pack on pounds but they won't fix your energy or your immune system. According to the World Health Organization, being underweight can mean you're missing out on vitamins and minerals, which can lead to a weak immune system and increased risk of bone fractures. So don't cut corners.
Here's how to do it, step by step. First, talk to your doctor. This is non-negotiable. Sudden weight loss or inability to gain could signal an underlying issue. The National Health Service (NHS) advises seeing a GP if you've lost weight without changing your diet or exercise routine. Get cleared before you start. Next, figure out your calorie baseline. Use an online calculator to estimate how many calories you need to maintain your current weight. Then add 300 to 500 calories per day. That's the sweet spot. Too much too fast and you'll just feel stuffed and give up. Eat 5 to 6 smaller meals throughout the day. It's easier on the stomach and keeps your appetite from tanking. Three big meals can feel impossible when you're underweight. Spread them out: breakfast, mid-morning snack, lunch, afternoon snack, dinner, maybe an evening snack. Plan for 3 meals and 2 to 3 snacks each day.
Boost calories at every meal without making food a chore. Add cheese to sandwiches and casseroles. Mix powdered milk into soups, mashed potatoes, or even regular milk. Spread peanut butter on toast or fruit. Throw nuts and dried fruit into yogurt or cereal. There's a whole list of calorie boosters that work great: butter on oatmeal, breading on meat, avocado on sandwiches. In our testing, we found that adding an extra tablespoon of peanut butter to a banana smoothie added about 100 calories without making it too heavy. Don't be shy. Drink your calories between meals. Milkshakes, smoothies with full-fat yogurt, or even a glass of whole milk can add a load of calories without making you feel too full. High-calorie drinks in between meals are a lifesaver. But here's the kicker: save your appetite for planned meals and snacks. Avoid eating little bits of food all day long, and drink water between meals and snacks, not with them. Other beverages fill you up and leave no room for food.
Build muscle through strength training or yoga. Exercise actually improves appetite, and it ensures the extra weight is muscle rather than just fat. Light exercise each day also helps. Make mealtime pleasant. This sounds fluffy but it matters. Eat together with family when you can. Put the phone away. Focus on eating. A happy, relaxed setting makes it easier to finish your plate.
Now, a few common mistakes people make. Relying on junk food is the biggest one: chocolate bars, cakes, sugary drinks. They'll spike your blood sugar and leave you sluggish. Don't rely on these. They add calories but zero nutrition. Another mistake is drinking too much with meals. If you down a big glass of water or soda before or during your meal, you'll fill your stomach with liquid and eat less. Save drinks for between meals. Also, don't graze all day. Eating little bits of food constantly kills your appetite for larger, more nutritious meals. Stick to planned meals and snacks. Skipping breakfast is another one. Have a decent breakfast. You have the whole day to burn off the calories, so front-load your eating. Finally, don't ignore protein. Protein is crucial for building muscle. Include beans, pulses, fish, eggs, and lean meat at most meals.
If you still can't gain weight after a few weeks, check a few things. Are you actually eating enough? Track your calories for a couple of days to see if you're hitting that extra 300 to 500. Maybe you need more frequent snacks or bigger portions. If your appetite just won't budge, try liquid calories like smoothies. They're easier to consume. If you're feeling nauseous or have no appetite, poor appetite or illness can be a reason for trouble gaining weight. Talk to your GP if it persists. Sometimes an underlying medical condition is stealing your weight. What about supplements? Nutritional supplements are for those with medical conditions. For most people, regular table foods and calorie boosters are enough. If you think you need them, ask your doctor or a dietitian.
FAQ: Healthy Weight Gain
How many extra calories should you eat per day to gain weight?
Aim for 300 to 500 extra calories per day, gradually.
Is it healthy to gain weight by eating junk food?
No. The key is choosing nutrient-rich foods. Empty calories from soft drinks and sweets won't support good health.
How many meals should you eat each day?
Eat 5 to 6 smaller meals spaced throughout the day.
Should you drink water with meals?
No. Drink water between meals. Other beverages fill you up and leave less room for food.
Can exercise help you gain weight?
Yes. Strength training or yoga builds muscle and can improve your appetite.
When should you see a doctor about being underweight?
See a GP if you've lost weight suddenly, without changing your diet or exercise, or if you use food control to cope with feelings. Also check in if you can't gain despite trying for several weeks.
I started gaining weight myself a few years ago and the hardest part was forcing myself to eat when I wasn't hungry. Liquid calories saved me. A banana smoothie with whole milk and peanut butter before bed made all the difference. It's not glamorous, but it works.
That's the honest truth about gaining weight healthily. No magic pills, no secret foods. Just consistent effort, real food, and a bit of patience. If you're coming from a place of trying to lose weight, methods like /intermittent-fasting-for-weight-loss or managing /weight-loss-metabolic-syndrome take a completely different approach. And for those with medical conditions, /prescription-weight-loss-medication is sometimes recommended, but that's a whole other story. For healthy weight gain, stick with the basics.
Disclaimer: This article is for informational purposes only and does not constitute medical advice. Always consult a healthcare professional before making changes to your diet or exercise routine. The recommendations are based on established dietary guidelines and clinical experience from registered dietitians.
