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Home arrow Nutrition arrow Weight Management arrow Why Can't I Gain Weight No Matter What I Eat? Reasons Beyond That

Why Can't I Gain Weight No Matter What I Eat? Reasons Beyond That

Written by Edibel Quintero, RD
Fact checked by Rosmy Barrios, MD
Last update: April 14, 2023
8 min read 1739 Views 0 Comments
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Many skinny people look for information online on how they can gain weight. Unfortunately, most of the information focuses on weight gain. But why do thin people eat a lot of food and can’t gain weight? This article explains why and advises on healthier ways to gain weight.

why can't i gain weight no matter what i eat

When performing online research, it’s likely to make you feel inferior if you identify as “thin” and are trying to gain weight. Most fitness information focuses on fat loss. Many people, however, have trouble gaining weight and struggle with their appearance.

It’s estimated that more than 2% of Americans are underweight, and some struggle to put on weight despite their best efforts.

You might fall into one of these categories, or you might overestimate how many calories you consume or underestimate how many calories you burn each day. Gaining weight and maintaining a healthy weight can be challenging for certain people, regardless of whether it’s due to genetics or an underlying medical issue.

This article discusses why it may be difficult for you to gain weight and what you can do about it.

5 Main Reasons Why You Can’t Gain Weight

There is undoubtedly a reason why your body seems to behave differently by consuming enormous amounts of food without adding weight. Several factors contribute to this problem. Here are a few frequent reasons why you might not gain weight while eating a lot.

#1 Lifestyle

Many people who have trouble gaining weight are unaware that they are not consuming enough calories. They will skip meals because of a hectic schedule or just not eat healthy foods for weight gain, such as fats or carbohydrates. Other people who also fail to gain weight are those who exercise but do not consume enough calories to balance off the loss. 

Significant, stressful life changes like a breakup, a death in the family, divorce, or being laid off can result in weight loss. Even positive changes like a new job, new relationship, house move, or wedding plans could be part of this. 

These things may trigger worry, which raises the risk of digestive issues, reduced appetite, and poor sleep, which are all causes of unintended weight loss.

#2 Diabetes

When insulin is insufficient, glucose cannot be absorbed from the blood into the body’s cells to use as energy. As a result, the body starts burning fat and muscle for fuel, causing weight loss. 

Unexpected weight loss is frequently observed in patients before a type 1 diabetes diagnosis, but it can also happen to people with type 2 diabetes.

There are two main types of diabetes – type 1 and type 2. A deficiency in insulin in the body causes type 1 diabetes, which is often diagnosed in childhood but can also be diagnosed later in life. Type 2 diabetes most commonly affects adults and is characterized by insulin resistance. 

#3 Hyperthyroidism

The thyroid gland is located in the neck and produces hormones regulating metabolic rate. If you have hyperthyroidism, your thyroid gland may produce too much thyroid hormone. 

Hyperthyroidism causes an increased metabolic rate, increasing the rate at which your body burns calories, causing you to lose weight. Your hunger will frequently increase, and even though you eat more, you may not gain weight.

Besides weight loss, other symptoms of hyperthyroidism can include an accelerated or irregular heartbeat, agitation, anxiety, trembling hands and fingers, and increased bowel movements. Your neck may also swell, and menstrual patterns may change for women.

#4 Gastrointestinal issues

Intestinal problems can prevent your body from properly absorbing food. You might not be able to gain weight even if you consume a lot because of malnutrition. This condition is called malabsorption.

Malabsorption can cause a deficit in any nutrient or specific deficiencies in proteins, lipids, carbohydrates, vitamins, or minerals. Despite consuming enough food, people with malabsorption typically lose or have trouble maintaining weight.

Malabsorption is common in people with certain digestive system diseases, such as irritable bowel syndrome, cystic fibrosis, Crohn’s disease, celiac disease, or ulcers. If you experience gas, abnormal bowel movements, pain in the abdomen, a greasy and light-colored stool with a foul smell, and no weight gain, consult a healthcare professional for a proper diagnosis. 

#5 Frequent exercise

Healthy eating and exercise are key to weight loss and maintenance. Some people can’t gain weight because they run every morning, cycle to and from work, attend an hour of pilates, play basketball with their friends, prepare for a marathon or Olympic swimming, and still engage in housework chores. 

If you incorporate too many physical activities into your daily life, your body may burn more calories than you realize. Those who exercise frequently burn more calories even while at rest than those who don’t, making it harder to sustain a calorie surplus and gain weight. 

How to Gain a Healthy Weight? 5 Actionable Tips

There is not only the “why” but also the “how.” Even if you have to add weight, you should still go about it healthily rather than just loading up on foods rich in fat and sugar. 

That will undoubtedly result in weight gain, but it may not be your body’s best course of action. Here are some healthy tips that will help you gain weight.

#1 Build muscle

Incorporating exercises to help you build muscle is essential in any weight gain journey. This includes push-ups, rowing, yoga, pull-ups, and other weight-gaining exercises. Although they burn calories, doing so may also increase your hunger and cause you to eat more.

#2 Eat meals more frequently

Some people who want to gain weight struggle to eat large portions at every meal. 

This might be because they struggle with poor appetite due to emotional or medical issues. If you have a lower appetite or something else that makes it difficult for you to consume as much from a standard three-meal routine – eating smaller, more frequent meals and snacks throughout the day, about every 2–3 hours, can help.

Whether supplementing meals with snacks or just eating more frequent, smaller meals throughout the day, you can consume enough calories to gain the weight you need without making yourself eat when you’re not hungry.

#3 Eat high-calorie foods

The most crucial thing you can do to add weight is to consume more calories than your body requires. This is known as creating a calorie surplus. To gain weight gradually and steadily, try to consume 300–500 calories per day more than you burn. Aim for approximately 700–1,000 more calories above your maintenance level daily.

Calorie calculators can help you determine your calorie needs. Remember that calorie calculators are just that – estimates. Your calorie needs may vary by a few hundred calories daily, depending on your needs.

Meals rich in lean proteins and veggies have fewer calories than meals rich in whole grains and healthy fats, which tend to have more calories. You can increase your calorie intake by adding cheese, nut or seed toppings, and wholesome side dishes. Try wheat toast, fruits like avocado, nuts, sunflower seeds, and oils such as olive oil.

#4 Drink protein shakes or meal replacement shakes

You may find it difficult to consume enough calories consistently if you’re trying to gain weight. One approach is taking advantage of liquid calories found in protein shakes, smoothies, or meal supplement shakes. 

These drinks give you a wholesome supply of vitamins, minerals, protein, carbohydrates, and fats, along with other nutrients, without making you feel too full.

The best thing about protein shakes is that you can try different ingredients that top your list of favorites to come up with your own combination. If you have trouble getting enough protein in your weight gain diet, protein supplements like whey protein can also be helpful.

#5 Enjoy condiments

Condiments, especially those rich in fats, can increase your calorie intake. If you’re using a lot of condiments like ketchup, you may be eating more calories than you realize. For example, one tablespoon of ketchup has 17 calories, while just two tablespoons of barbecue sauce will give you anywhere from 45 to 70 calories on average.

What to Eat to Gain Weight Fast?

As stated above, the main cause of gaining weight is eating more calories than you burn throughout the day. Increasing the amounts of healthy fats and protein in your diet is necessary when trying to gain weight, along with eating more meals each day and exercising to build muscles.

Consuming junk foods and unhealthy fats to gain weight is one thing you shouldn’t consider. These foods will only increase body fat around your belly and may lead to major long-term medical conditions such as diabetes, obesity, and heart problems.

Here’s a list of healthy foods you can eat to quickly increase weight.

Milk: Milk is a good source of vitamins, minerals, calcium, carbohydrates, and proteins. Both casein and whey proteins are present, making this drink a great source of protein. 

Rice: Rice is a calorie-dense food and a rich source of carbohydrates critical to gaining weight. Approximately 205 calories can be found in one cup of rice, which might lead to weight gain. You can eat white rice every day as it helps to add weight safely and quickly.

Dried fruits: Dried fruits such as almonds, cashews, and walnuts are packed with antioxidants, calories, proteins, and micronutrients and are naturally high in sugar content, making them great for gaining weight. You can eat them raw or roasted or add them to smoothies or yogurt.

Red meat: Red meat is an excellent source of protein that promotes weight gain and muscle growth. It has leucine and creatine, which are important for increasing muscle mass. Protein and fat in steak and other red meats also increase weight.

Whole eggs: Eggs offer a balance of superior proteins and beneficial fats. A large raw egg with a shell contains about 74 calories. Eating the entire egg is crucial since all the nutrients are in the yolk. You can easily eat three eggs a day if you don’t have an intolerance to eggs.

A Word From a Nutritionist

Consuming more calories than you burn while eating various nutritious meals is the best approach to healthily gaining weight. Despite having a lot of calories, processed meals lack the nutritional content and health benefits that natural, whole foods offer.

One of the best ways to improve your health and diet quality is to cut back on highly processed foods. You can remake your favorite processed meals in your kitchen by giving them a healthier spin. This allows you to experiment with intriguing new ingredients while giving you ultimate control over what goes on your plate.

Consult a healthcare professional before starting your journey to a healthy weight gain. A hidden health issue may cause being underweight that cannot be solved by dietary adjustments alone. Your doctor will help you understand why you’re having difficulties gaining weight, monitor your progress, and advise you accordingly.


Various foods and supplements can promote weight gain. But rather than trying to stuff yourself with tons of sweet or fatty foods, opt for high-calorie foods that give you energy and help you gain muscle mass without the unhealthy fats that may harm you.

Lifting weights is also essential so that the extra calories from foods and high-calorie snacks are utilized to build muscle rather than just fat.

Any healthy individual can gain weight. However, for certain people, it may be more difficult due to their appetite, physical activities, or simply lack of time to focus. You must, therefore, organize your daily meal plan. 

Written by Edibel Quintero, RD
Edibel Quintero is a medical doctor who graduated in 2013 from the University of Zulia and has been working in her profession since then. She specializes in obesity and nutrition, physical rehabilitation, sports massage and post-operative rehabilitation. Edibel’s goal is to help people live healthier lives by educating them about food, exercise, mental wellness and other lifestyle choices that can improve their quality of life.
The article was fact checked by Rosmy Barrios, MD
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