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

James Cunningham, BSc, CPT
Published by James Cunningham, BSc, CPT | Staff Writer & Senior Coach
Last updated: May 21, 2024
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To gain weight quickly, focus on nutrient-dense, calorie-rich foods like nuts, avocados, and protein-packed options.

In my years as a fitness trainer, incorporating weightlifting into client routines consistently proved effective for weight gain and physique improvement. Regular consultations with other experts provide valuable insights into assisting underweight clients.

Addressing the challenge of feeling too thin is not daunting. This article guides you toward fast and effective results, highlighting factors contributing to weight gain and offering tips on foods for quick and safe weight gain.

Quick Summary

  • Incorporate nutrient-dense, calorie-rich foods like nuts, avocados, and protein-packed options to achieve quick and safe weight gain.
  • Extreme and prolonged underweight may pose higher health risks, so it is important to maintain a healthy weight.
  • Maintaining a consistent approach to weight gain not only yields physical benefits but also contributes to improved mental health, with a CDC study showing a 34% variance in health risk explained by z-scores.
  • Adopting healthy weight-gain strategies, including a nutritious diet, targeted exercises, and proper supplements, is crucial for effective results.

9 Tips on How to Gain Weight

Gaining a healthy weight involves focusing on nutrition, training, and consistency. To achieve this, here are nine tips you can consider.


1. Eat Constantly (At Least Every 4 Hours)


Going without food for extended periods can lead your body to rely on stored fat and muscle mass for fuel.

To prevent this, aim to have meals and snacks every three to five hours, boosting your calorie intake—an essential factor for weight gain.

2. Stock Up On Protein


Muscles are composed of protein, making it a crucial element in your diet. Studies suggest that a protein-rich diet aids in converting excess starch and sugar calories into muscle [1].

To support weight gain, target 0.8-1.2 grams of protein per pound of body weight daily. If reaching this goal is challenging through regular meals, consider supplements like whey protein or protein bars.

3. Combine Your Foods For Maximum Benefit

Improve your meals and snacks by combining a banana with peanut butter and toast and pairing crackers with hummus along with a glass of milk.

Ensure you incorporate carbs and fats into your diet; while they may not be as filling as protein, they are calorie-dense and play a valuable role.

4. Eat Energy-Packed, Nutrient-Dense Foods


Optimize your calorie intake by selecting nutrient-rich foods with maximum carbohydrates, proteins, and fats in smaller servings.

Dehydrated options like dried fruit and beef jerky are good for providing calories in small portions, making them suitable for portion-control diets.

5. Drink Your Calories

fruit juice

Opt for calorie-dense smoothies to efficiently increase your calorie intake without feeling overly full.

Replace regular water with thick, cream-based liquids like 100 percent fruit juice, organic milk, or smoothies to effortlessly add extra calories to your daily diet.

Related: Should I Drink Milk Before a Workout?

6. Eat Right Before Bed


Consume a healthy bedtime snack to provide your body with essential fuel, preventing it from tapping into fat and muscle stores.

Choose calorie-rich options like whole grain pasta with a creamy sauce or lean proteins such as beans and chicken with cheese coating. Your body will appreciate it!

7. Be Patient

Yoda and Be Patiend meme

Weight gain is a gradual process, so be don't be concerned if your initial efforts to build muscle appear to result in some extra body fat.

Stay flexible with your expectations, adjusting your meal plan as needed to find what works best for you to build lean muscle.

8. Track Your Progress


Track your progress by recording every calorie for the first few months to identify patterns and gain a true understanding of your daily food intake.

If you experience a particularly good week, refer to your records and try a similar eating approach to maintain that positive feeling.

9. Eat Faster


Speed up your eating to trick your body into consuming more before it signals fullness, as this process takes about twenty minutes.

For an added challenge, dine with others sharing similar weight gain goals and turn it into a friendly competition to see who can finish their meal the fastest.

10 Best Foods To Eat To Gain Weight

Dessert on a plate

The most effective way to gain weight is by consuming nutrient-dense whole foods that provide calories without causing excessive fullness, allowing for consistent snacking throughout the day.

Here are the 10 best foods for weight gain:

  1. Condiments
    Enhance meals with calorie-rich options like mayonnaise, sour cream, Greek yogurt, gravy, butter, and salt. Making food tastier increases the likelihood of consuming larger quantities.
  2. Desserts
    Choose nutrient-dense, calorie-filled options like oatmeal cookies and zucchini bread to support weight gain goals.
  3. Dried Fruit
    Opt for dried fruit, with its reduced water content, offering more calories without causing excessive fullness. For example, an ounce of banana chips provides 147 calories, surpassing the calorie content of a regular banana.
  4. Fats And Oils
    Incorporate healthy fats like extra virgin olive oil, butter, avocado oil, and coconut butter. Fats, with twice as many calories per gram as proteins and carbs, are a smart choice for calorie addition.
  5. Fresh, Dense Fruits
    Choose fruits with lower water content, such as mangoes and avocados, for nutrient-rich, calorie-dense options.
  6. High-fat Dairy Products
    Embrace whole milk, full-fat yogurt, cheese, and cream for calorie-rich dairy options, provided your body tolerates them well.
  7. Meat
    Opt for fattier cuts like marbled steaks and 80/20 ground beef. Include chicken, beef, pork, lamb, and fatty fish like salmon for both calorie content and health benefits.
  8. Nuts And Seeds
    High in fiber and protein, nuts and seeds provide around 200 calories per ounce. Add them to soups, salads, and cereals for an easy way to increase calorie intake.
  9. Starchy Vegetables And Tubers
    Choose vegetables like potatoes, peas, and sweet corn for higher calorie content and natural fiber. Combine starchy vegetables with leaner greens for a balanced approach.
  10. Whole Grains
    Mixing granola, oats, brown rice, and whole grain bread into other foods provides an extra caloric punch. Flax meal and wheat germ, with about 20 calories per tablespoon, also offer 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

Why Is Gaining Weight Important?


Gaining weight is important for underweight individuals as it helps them achieve and sustain healthier body weight, reducing the elevated health risks associated with prolonged underweight conditions.

Although being overweight poses significant health risks, an extreme and prolonged underweight state may lead to even higher health risks, as noted by the National Institute of Health [2].


From my experience working with underweight clients, I've observed that they often experience heightened stress and a weakened immune system, resulting in inconsistency in their workout schedules.

What Is the Definition of Being Underweight?


Being underweight is typically defined as having a body mass index (BMI) below 18.5, as per the National Institute of Health guidelines. To stay healthy, aim to stay above this threshold [3].

If you're a muscular athlete, keep in mind that your BMI might not be accurate for you. Don't assume poor health just based on the BMI scale, which categorizes you as underweight.

Genetics can make females over three times as likely as males to be underweight, but being naturally slender doesn't necessarily mean poor health.

Check out this tool called Lumen to track your metabolism.

5 Foods To Avoid For Weight Gainers

Woman avoiding food

Even for those aiming to gain weight, it's crucial to choose the right kinds of foods and steer clear of "empty" calories that fill you up without contributing to weight gain.

Here's a list of foods that individuals working on weight gain should avoid:

  1. Low Fat/Low Cal Foods
    Weight gainers should skip diet foods. Choose full-fat options and prioritize higher-calorie items. Consider bagels over English muffins for a more substantial choice.
  2. Candy
    Processed sugars aren't ideal. Candy might fill you up without adding bulk. If you want something sweet, try mixing honey or chocolate into nut butter.
  3. Crackers
    Skip simple carbohydrates as they quickly turn into glucose, promoting fat, not muscle, gains. Opt for whole grains for a healthier choice.
  4. Fast Food
    Despite being calorie-dense, it's not the right kind of calories. Cook your food to avoid artificial ingredients and preservatives for a healthier lifestyle.
  5. Watery fruits and vegetables
    While citrus and berries are nutrient-rich, they may not contribute many calories.

Choose starchy fruits like mangoes and bananas for a more calorie-dense option. (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


You can gain weight while working out by adopting intelligent exercise strategies and modifying routines for optimal weight gain, complementing your diet.

Here are some essential tips for a healthy approach to reducing body fat and building muscle:

  • Track Your Progress
    Monitor strength-training numbers for consistency and motivation.
  • Never Train Hungry
    Avoid starting workouts on an empty stomach to prevent muscle breakdown. Snack before and have a substantial post-workout meal.
  • Ditch Cardio, Embrace Strength Training
    Prioritize weightlifting multiple times a week for muscle mass and overall weight gain. Consider shorter runs or long walks for cardio.

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.

  • Consume a Carb & Protein Drink During Workouts
    A study on the effect of dietary protein content on weight gain suggests that a protein-rich diet helps convert excess starch and sugar calories into muscle. Maintain fuel with a 2:1 carb-to-protein shake during exercise.
  • Prioritize Ample Rest
    Ensure at least eight hours of sleep per night for optimal muscle repair. Consider an afternoon nap or massage between workouts for added benefits.

Other Helpful Tips To Gain Weight

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

  • Don't drink before meals
    Avoid consuming empty calories before eating.
  • Use a bigger plate
    Increase your food intake by using a larger plate; it can influence you to eat more.
  • Pump up your food with extras
    Easily boost calorie intake without feeling overly full by adding ingredients like blue cheese to your salad or creamer to your coffee.
  • Eat your protein first and vegetables last
    Ensure your body gets sufficient protein by prioritizing calorie-dense foods on your plate.
  • Additionally, taking high-quality multivitamins helps in staying on track with progress by bridging nutritional gaps.
  • Don't smoke
    Quitting smoking is a positive step for overall health, and it may lead to weight gain, which is a natural part of the process.
  • Go out to eat
    Take advantage of generous restaurant portions to increase calorie intake. Choose hearty options over lighter ones like tofu and resist the urge to opt for a to-go box.

Additionally, taking high-quality multivitamins helps in staying on track with progress by bridging nutritional gaps.


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About The Author

James Cunningham, BSc, CPT
Staff Writer & Senior Coach
James Cunningham, BSc, CPT holds a BSc degree in Sport & Exercise Science from University of Hertfordshire. He's a Health & Performance Coach from London that brings a unique blend of academic knowledge of health supplements and practical exercise experience to the table for his readers.
Learn more about our editorial policy
Dr. Harshi Dhingra, MBBS, MD is a published peer-reviewed author and renowned physician from India with over a decade of experience. With her MBBS from Bharati Vidyapeeth and an MD from Rajiv Gandhi University, she actively ensures the accuracy of online dietary supplement and medical information by reviewing and fact-checking health publications.
Learn more about our editorial policy
Dr. Kristy June Dayanan, BS, MD is an author with a BS degree from University of the Philippines and an MD from University of Perpetual Help System. Her ability to simplify medical science complexities and dietary supplement jargon for the average reader makes her a valued medical fact checker and reviewer.
Learn more about our editorial policy

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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.

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