Total Shape is a reader-supported site. Purchases made through links may earn a commission. Learn more.

How to Gain Weight FAST If You're Underweight (15+ Tricks)

Tyler Sellers
Published by Tyler Sellers
Fact checked by Donald Christman, BHSc FACT CHECKED
Last updated: January 17, 2023

Gaining weight healthy and faster for men and women isn't complicated as many people perceive. As a fitness trainer, I have guided numerous clients into gaining weight, especially if they are underweight. It all starts by selecting the right workout technique and also eating the right foods.

It might take you up to three months to get instant and noticeable results for both men and women. I have consulted different doctors and nutritionists for this guide. Additionally, I have conducted thorough research on attaining your weight goals the right way.

Remember, the kind of meal you eat influences the nutrients ingested in your body. Similarly, it determines if you will have sufficient energy to work out.

Quick Summary

  • To gain weight faster, especially if you are underweight, eat healthy meals  at the intervals of at four to five hours. Such meals are proteins, meals rich in minerals and vitamins and carbohydrates.
  • Eat healthy meals as they contain important nutrients needed by the body.
  • Combine your meals for maximum benefit. You can mix fruits, proteins and calories in your food.
  • Don't drink fluids before taking your meal. It only fills your stomach with empty calories whereas your body needs nutrients to help you gain weight.

Are You Underweight?

By common consensus, being underweight is defined as having a body mass index (BMI) that is below 18.5.

This is the threshold that you need to stay above in order to be at your healthiest.

Alternatively, a BMI over 25 is considered overweight, so you want to keep yourself within this middle range (unless you are a muscular athlete, in which case the BMI is largely inaccurate). [1]

You don't have to assume you are unhealthy just because the BMI scale labels you as underweight.

Females are over three times more likely to be underweight than males, and oftentimes the only reason is genetics. Lots of people are naturally predisposed to be as skinny as tooth picks, and they are perfectly healthy that way.

Health Problems with being underweight

Being underweight can have some scary consequences for your quality of life - and might just end it prematurely. Being underweight can be even more dangerous for your health than being overweight because a lack of fat can put excess strain on your heart, leading to serious problems. [2]

Below are some of the main health problems that affect people that are underweight.

  • Organ Failure: In extreme cases, being underweight can put severe stress on your internal organs and even cause them to fail. If your liver or kidneys fail it becomes hard for doctors to keep you alive.
  • Heart Issues: Being too thin causes you to lose muscle mass, and your heart is one of the most important muscles in your body. Being underweight can cause the walls of your heart to thin over time, putting you at risk of an irregular heart beat or pulmonary collapse.
  • Compromised Immune System: Being underweight puts more stress on your immune system, making it easier for you to catch the flu or other nasty infections.
  • Decreased Fertility: Women that are underweight are less likely to have a regular period, which makes it much harder for them to get pregnant and carry a pregnancy to full term.
  • Lack of Vitamins and Minerals: Especially if you are still growing, vitamins and minerals are crucial for maintaining overall health and ensuring that you don't have severe problems from deficiencies in the future.
  • Bone Problems: Calcium is especially important for maintaining full body bone health, and being underweight means you won't get an appropriate supply. Not consuming enough iron can increase your risk of osteoporosis.
  • Anemia: Like calcium, iron is an important supplement for every diet. Not getting enough can lead to anaemia, which makes you feel like you are in an exhausted fog all day.

Being underweight for long periods of time will put your body at risk of developing these medical conditions and others

Why Is Gaining Weight So Hard?

You might want to try bulking up in a matter of weeks by stuffing yourself with high calorie foods, but that never works.

If gaining healthy weight was that simple, there would be no reason to write this article. The truth is that gaining weight is a lot more complex.

Though it's easy to think otherwise, all calories are not equal, and every body processes calories differently.

A pan of brownies might add three pounds to your friend's middle without leaving so much of a trace on you. It may seem unfair, but everyone's metabolism is different and we all have different caloric needs to stay healthy.

Check out this tool called Lumen to track your metabolism.

If you can eat everything you want and still not gain an ounce, then you likely have a fast metabolism (or an internal parasite - get that checked out!). This can make gaining weight both expensive and highly frustrating.

In order to gain weight, you'll have to work against your body's natural abilities and essentially “outsmart” it. If you truly want to gain weight through your diet, get ready to trick your body into eating even when you aren't hungry.

9 Tips on How to Gain Weight

Learning how to gain healthy weight takes a lot of hard work and dedication. Binging on soda and donuts can only get you so far and will likely destroy your health in the process.

That's why the main ingredients to gaining weight consists of 3 factors: nutrition, training and consistency.

Though this is pretty simplified, if you hit all these correctly, you will see you weight increase.

Here are other tips to keep in mind while you gain weight:

1. Eat Constantly (At Least Every 4 Hours)

Going for long periods without food stops your body from getting the fuel it needs, meaning it will turn to your stored fat and even muscle mass instead.

If you want to stop your body from feeding on itself, you will need to eat meals and snacks every three to five hours.

This will increase your calorie intake, one of the important factors of weight gain.

2. Stock Up On Protein

Your muscles are made of protein, which is why you need to fill your diet with it. Better yet, some studies have shown that a protein-rich diet helps you turn excess starch and sugar calories into muscle as well. [3]

For gaining weight, it’s smart to aim for 0.8-1.2 grams of protein per pound of body weight daily. If you have a hard time getting enough protein in your diet, supplements like whey protein and protein bars can be very helpful.

3. Combine Your Foods For Maximum Benefit

With every meal and snack, always strive to combine three or more different food groups.

Mix your banana with peanut butter and toast, and add a glass of milk to your crackers with hummus.

The more varied the foods you eat, the greater the nutritional pool your body can pull from.

Don't restrict yourself from carbs or fats, as they are calorie dense and won't fill you up as much as protein.

4. Eat Energy-Packed, Nutrient-Dense Foods

Make your calories work for you by choosing foods that are as nutrient rich as possible. You want to get the maximum carbohydrates, proteins and fats in the smallest serving.

This gives you the calories you need without feeling too full. Dehydrated foods like dried fruit and beef jerky are excellent because they fill you with calories in tiny portions.

This is great if you're on a portion control diet.

Nut butters are also a smart choice, especially when mixed together with other ingredients like rolled oats and chocolate chips.

5. Drink Your Calories

fruit juice

500 calories of liquid won't make you feel as full as the equivalent in food, so filling up on calorie-dense smoothies is a smart choice for gaining weight without leaving you feeling sick or bloated.

Instead of drinking water throughout the day, make a habit of drinking thick, cream-based liquids and you'll find it easy to add hundreds of extra calories every day. Chugging glasses of 100 percent fruit juice, organic milk or smoothies are a smart choice.

Stick with smoothies over milkshakes because you can modify them more to be filled with beneficial ingredients like nut butters, protein powders and even whey supplements.

Related: Should I Drink Milk Before a Workout?

6. Eat Right Before Bed

Sleep is an incredibly important time for our bodies, and it's the time when they repair and regenerate themselves while also building up muscle and lean tissue.

Eating a healthy snack before you fall asleep gives your body all the fuel it needs to perform these essential tasks and helps to ensure that it won't be pulling from your fat and muscle stores instead.

To give yourself plenty of calories without feeling stuffed, opt for carbohydrates like whole grain pasta with a creamy sauce or lean proteins like beans and chicken coated with rich cheese. Your body will thank you!

7. Be Patient

Yoda and Be Patiend meme

Putting on weight is never quick or easy, so don't expect to see dramatic results overnight.

Be flexible with your expectations and adjust and update your meal plan as you go to ensure you are finding the methods that your body best responds to.

Don't be alarmed if your initial attempts to gain muscle mass seem to result only in extra body fat.

Increasing your calorie counts will almost inevitably lead to some fat gain, but with the right exercise routines you can make sure most of your gains come the way you want them to- as lean muscle.

8. Track Your Progress

The best way to stay encouraged and inspired to keep going is to track your progress in order to see how far you've come.

Spend your first few months writing down every calorie that goes into your body.

Not only does this help you find patterns of what works for you, it gives you a better understanding of how much food you are truly eating in a day.

If you find yourself feeling especially good one week, you can look back at your records and eat in a similar way to see if you can maintain that good feeling.

9. Eat Faster

It takes your body twenty minutes to send a signal to your brain when it's full, so trick it into accepting more food by eating as fast as you can.

Never put your utensils down when eating and make sure there is constantly food in your mouth.

For an extra challenge, make sure to eat meals with people with similar weight gain goals as you,and then make it a competition to see who can eat their food the quickest.

Though this technique might not do much for your dating life, it is guaranteed to help you gain weight.

10 Best Foods To Eat To Gain Weight

Dessert on a plate

The best way to gain weight is to eat a diet filled with nutrient-dense whole foods that fill you with calories without keeping you so full that you can't snack throughout the day.

Gaining weight should always be done with the goal of increasing your overall health.

It is also an important part of that process is eating foods that both keep you healthy and help you to gain weight.

Here are 10 best foods to gain weight.

  • Condiments - Garnish your meals with special, calorie rich condiments like mayonnaise, sour cream, Greek yogurt, gravy and others. Butter and salt is also absolutely not off limits. Remember, the tastier you can make your food, the more likely you are to eat lots of it.
  • Desserts - Rich, calorie filled desserts are your new best friend. Stick with ones that have lots of nutrients as well as fat, like oatmeal cookies and zucchini bread.
  • Dried Fruit - Because the water content has been evaporated out, dried fruit fills you with more calories while leaving you less full. An ounce of banana chips provides you with 147 calories, far more than an ounce of regular banana can get you.
  • Fats And Oils - Because fat has twice as many calories per gram as proteins and carbs, it is a smart way to add calories to your diet without feeling overly full. Extra virgin olive oil, butter, avocado oil and coconut butter are all smart types of fat to eat.
  • Fresh, Dense Fruits - You want to avoid watery options like grapes and citrus (though they can make great juices). Your best bet is to snack on mangoes and avocados, which are full of nutrients, calories, and, in the case of avocados, healthy fats.
  • High-fat Dairy Products - Whole milk, full-fat yogurt, cheese, and cream are your new calorie-filled favorites, so if your body can handle health benefits of dairy, be sure to fill your diet with it.
  • Meat - The fattier cuts you can get, the better, so be sure to invest in the marbled stakes and 80/20 ground beef. Choose chicken, beef, pork, and lamb over extra lean varieties like rabbit. Fatty fish like salmon are especially healthy because of their omega-3 fatty acid levels.
  • Nuts And Seeds - High in fiber and protein, nuts and have about 200 calories per ounce. Because they can be added to just about anything, nuts and seeds are a great way to pump up the calorie content in your soups, salads and cereals.
  • Starchy Vegetables And Tubers - Potatoes, peas and sweet corn have more calories than other vegetables, and they provide you with a perfect source of natural fiber. For the best benefit, mix starchy vegetables with leaner greens, like broccoli on a baked potato.
  • Whole Grains - Fill your diet with granola, muesli, oats, brown rice, and whole grain bread in order to add calories to your diet. You can also mix grains into your other foods for an extra boost. Flax meal and wheat germ have about 20 calories per tablespoon, and also provide you with fiber and healthy omega-3 fatty acids.

The most important thing you can do to gain weight is to create a calorie surplus, meaning you eat more calories than your body needs.
- Kris Gunnars, BSc, Healthline

5 Foods To Avoid For Weight Gainers

Even for weight gainers, there's a limit to how much food your body can handle in a day.

Because of this, it's important to fill your body with the right kinds of foods and to avoid “empty” calories that fill you up without providing any weight-gaining benefit.

With this in mind, here is a list of foods that everyone who is trying to gain weight should avoid.

  • Anything low fat/low cal: For the weight gainer, diet food should be avoided at all costs. Stick to full fat options and always opt for higher calorie items. You want to be filling up on bagels, not English muffins.
  • Candy: Processed sugars are never a good idea, and candy will fill you up without adding any bulk. If you crave sweetness, mix some honey or chocolate into a nut butter instead.
  • Crackers: Avoid simple carbohydrates at all costs because they will break down into glucose quickly, causing any weight gains to come from fat, not muscles. Stick with whole grains instead.
  • Fast Food: It might be full of calories, but they aren't the kind you want in your body. Stay away from artificial ingredients and preservatives by taking the time to cook your own food instead. It's simply a healthier way to live.
  • Watery fruits and vegetables: Citrus and berries may be full of nutrients, but they'll also make you full without lots of calories. Stick with starchy fruits like mangoes and bananas (read all about controversy about banana and weight loss).

Binging on soda and donuts may help you gain weight, but it can destroy your health at the same time. If you’re underweight, you want to gain a balanced amount of muscle mass and subcutaneous fat rather than a lot of unhealthy belly fat.
- Kris Gunnars, BSc, Healthline

How To Gain Weight While Working Out


In many ways, your exercise plan is just as important for achieving your weight gain goals as your diet.

Many people avoid exercise altogether when they are trying to gain weight because they think it will cause them to burn too many calories, and this is a big mistake.

Not exercising when you increase your calorie counts is a good way to ensure that all the weight you are gaining becomes unhealthy belly fat, not productive muscles.

By exercising smart and switching out some of your routines to maximize your weight gaining potential, you will start to add on weight in no time.

With ideal levels of training, supplementation and the perfect diet, it's possible for the average male body to build about half a pound of muscle a week.

This is the maximum level your body can handle. If you are gaining more weight than this per week, you are gaining fat, not muscle. [4]

It takes surprisingly little exercise to start building up your muscles, so long as you work out with heavy weights and work out consistently. Here are other tips for helping you to strip down your fat and bulk up your muscles in healthy ways.

  • Get Lots Of Rest - Your body needs sleep, and getting at least eight hours of sleep a night is critical for it to have the time to perform the muscle repairs it needs. For even better benefits, take an afternoon nap or get a massage between workouts.
  • Track Your Progress - For best results, track all your strength-training numbers so that you know how often to increase reps or add on more weight. Looking at the numbers will keep you consistent, and also motivate you with how far you've come.
  • Never Train Hungry - One of the worst things you can do is to start your workouts starving. This will force your body to find alternate fuel sources like your hard-earned muscles for energy. Have a heavy snack 30 minutes before you start to exercise and try to eat your biggest meal of the day right after your workout.
  • Ditch the Cardio and start strength training - By lifting weights several times a week, you will be building muscle mass that can lead to overall weight gain. It's not necessary to give up your cardio altogether - just go on shorter runs or take long walks instead.
  • Drink A Carb & Protein Drink While You Workout - Eating beforehand is important, but even more beneficial for your body is to have a constant supply of fuel while working out. Mix up a protein shake that's a 2:1 ratio of carbohydrates to protein and you'll keep yourself full and hydrated during your workout.

Other Tips To Consider

The proper combination of a healthy diet, strength-building exercises and dietary supplements will help with your weight gaining goals, but here are some final tips to help you go the extra mile.

  • Don't drink before meals: The last thing you want to do is fill your stomach up with empty calories.
  • Use a bigger plate: We are programmed to eat what's in front of us, so by piling on the food you'll be far more likely to eat more.
  • Pump up your food with extras: Add the blue cheese to your salad and the creamer to your coffee. It's an easy way to add extra calories without filling you up.
  • Eat your protein first and vegetable last: Fill up on the calorie-dense foods on your plate first to ensure your body gets all the protein it needs.
  • Don't smoke: Smokers tend to weigh less, and if you have to quit all the better; many former smokers gain weight when they first try to quit.
  • Go out to eat: Restaurant portions tend to be massive, so you're bound to add some bulk if you eat out enough. Just don't take the excuse of a to-go box, and go for big meals, not something light like tofu.

Consistency Is Key To Gaining Weight

Gaining weight may be tricky, but it's certainly not impossible. With the right combination of a healthy, calorie-filled diet, and a proper strength-building exercise routine, you will be on your way to bulking up before you know it.

Remember to eat clean healthy foods, consume more calories everyday than your body can burn, and to supplement your diet with weight lifting exercises several times a week.

Once you get into a healthy routine, you might surprise yourself how efficiently your body can start to pile on the pounds of muscle.

Now we want to hear from you. What are your best secrets for effective weight gain?

Do you have a supplement you swear by or a workout routine that leaves you feeling ripped?

Please share your tips with us and we'd love to explore your ideas farther.


  1. Angus Chen, If BMI Is The Test Of Health, Many Pro Athletes Would Flunk, Retrieved from
  2. Ringbäck Weitoft G, Eliasson M, Rosén M - Underweight, overweight and obesity as risk factors for mortality and hospitalization. Retrieved from
  3. G Bray - Effect of Dietary Protein Content on Weight Gain, Energy Expenditure, and Body Composition During Overeating. Retrieved from
  4. C Finn - How Fast Can You Expect to Build Muscle Naturally? Retrieved from
Was this article helpful?

About The Author

You May Also Like

One thought on “How To Gain Weight Fast for Men & Women
The Safe & Healthy Way

  1. I’ve been trying to gain weight for 3 months now but I’m not seeing any improvements in my weight because I was just working on increasing my calorie intake with no exercise. Good thing I saw your article. I’ll follow those 9 tips you have provided. These are golden. Thanks.

Write a Reply or Comment

Your email address will not be published. Required fields are marked *