Approximately 66% of individuals in the US fall into the category of being overweight or obese.
Conversely, a significant number face the challenge of being excessively thin.
Such a condition is alarming, as being too lean can have health implications comparable to obesity.
Moreover, numerous individuals, even if not categorically underweight, aim to build muscle mass.
Regardless of whether you’re medically underweight or just aiming to pack on muscle, the foundational guidelines remain consistent.
Explore this article for a straightforward approach to effectively and healthily increase weight.
What does underweight mean?
Being underweight is defined as having a body mass index (BMI) below 18.5. This is estimated to be less than the body mass needed to sustain optimal health.
Conversely, over 25 is considered overweight, and over 30 is considered obese.
Use this calculator to see where you fit on the BMI scale and how many calories you should eat to gain weight.
Calorie Calculator & Counter
Enter your details in the calculator below to figure out how many calories you should be eating per day to either maintain, lose, or gain weight.
However, keep in mind that there are many problems with the BMI scale, which only looks at weight and height. It does not take muscle mass into account.
Some people are naturally very skinny but still healthy. Being underweight according to this scale does not necessarily mean that you have a health problem.
Being underweight is about 2–3 times more common among girls and women, compared to men. In the US, 1% of men and 2.4% of women 20 years and older are underweight.
Summary: Being underweight is defined as having a body mass index (BMI) below 18.5. It’s much more common in women and girls.
What are the health consequences of being underweight?
Obesity is currently one of the world’s biggest health problems.
However, being underweight may be just as bad for your health. According to one study, being underweight was associated with a 140% greater risk of early death in men, and 100% in women.
In comparison, obesity was associated with a 50% greater risk of early death, indicating that being underweight may be even worse for your health.
Another study found an increased risk of early death in underweight men, but not women, suggesting that being underweight may be worse for men.
Being underweight can also impair your immune function, raise your risk of infections, lead to osteoporosis and fractures, and cause fertility problems.
What’s more, underweight people are much more likely to get sarcopenia (age-related muscle wasting) and may be at greater risk of dementia.
Summary: Being underweight can be just as unhealthy as being obese — if not more. Underweight people are at risk of osteoporosis, infections, fertility problems, and early death.
Causes of underweight
Several medical conditions can cause unhealthy weight loss, including:
Suggested read: Top 15 reasons you’re not losing weight on a low-carb diet
- Eating disorders: This includes anorexia nervosa, a serious mental disorder.
- Thyroid problems: Having an overactive thyroid (hyperthyroidism) can boost metabolism and cause unhealthy weight loss.
- Celiac disease: The most severe form of gluten intolerance. Most people with celiac disease don’t know that they have it.
- Diabetes: Having uncontrolled diabetes (mainly type 1) can lead to severe weight loss.
- Cancer: Cancerous tumors often burn large amounts of calories and can cause someone to lose a lot of weight.
- Infections: Certain infections can cause someone to become severely underweight. This includes parasites, tuberculosis, and HIV/AIDS.
If you’re underweight, you may want to see a doctor to rule out any serious medical conditions.
This is particularly important if you have recently started losing large amounts of weight without even trying.
Summary: Several medical conditions can cause unhealthy weight loss. If you’re underweight, see a doctor to rule out a serious health problem.
How to gain weight the healthy way
If you want to gain weight, it’s very important to do it right.
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.
There are plenty of normal-weight people who get type 2 diabetes, heart disease, and other health problems often associated with obesity.
Therefore, it’s essential to eat healthy foods and live an overall healthy lifestyle.
The next chapter looks at several effective ways to gain weight fast, without ruining your health at the same time.
Summary: When aiming to gain weight, it is crucial to prioritize the consumption of nutritious foods.
Eat more calories than your body burns
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.
Suggested read: How long does it take to gain weight?
You can determine your calorie needs using this calorie calculator.
If you want to gain weight slowly and steadily, aim for 300–500 calories more than you burn each day according to the calculator.
If you want to gain weight fast, aim for around 700–1,000 calories above your maintenance level.
Keep in mind that calorie calculators only provide estimates. Your needs may vary by several hundred calories per day, give or take.
You don’t need to count calories for the rest of your life, but it helps to do it for the first few days or weeks to get a feel for how many calories you’re eating.
Summary: You need to eat more calories than your body burns to gain weight. Aim for 300–500 calories per day above your maintenance level for slow weight gain or 700–1,000 calories if you want to gain weight fast.
Eat plenty of protein
The single most important nutrient for gaining a healthy weight is protein.
Muscle is made of protein and without it most of those extra calories may end up as body fat.
Studies show that during periods of overfeeding, a high-protein diet causes many of the extra calories to be turned into muscle.
However, keep in mind that protein is a double-edged sword. It’s also highly filling, which may reduce your hunger and appetite significantly, making it harder to get in enough calories.
If you’re trying to gain weight, aim for 0.7–1 grams of protein per pound of body weight (1.5–2.2 grams of protein per kilogram). You can even go above that if your calorie intake is very high.
High-protein foods include meats, fish, eggs, many dairy products, legumes, nuts, and others. Protein supplements like whey protein can also be useful if you struggle to get enough protein in your diet.
Summary: Protein forms the building blocks of your muscles. Eating sufficient protein is required to gain muscle weight instead of just fat.
Fill up on carbs and fat and eat at least 3 times per day
Many people try restricting either carbs or fat when trying to lose weight.
This is a bad idea if your goal is to gain weight, as it will make it harder to get in enough calories.
Eat plenty of high-carb and high-fat foods if weight gain is a priority for you. It is best to eat plenty of protein, fat, and carbs at each meal.
It is also a bad idea to do intermittent fasting. This is useful for weight loss and health improvement but can make it much harder to eat enough calories to gain weight.
Suggested read: Does weightlifting help women lose weight?
Make sure to eat at least three meals per day and try to add energy-dense snacks whenever possible.
Summary: To gain weight, eat at least three meals per day and make sure to include plenty of fat, carbs, and protein.
Eat energy-dense foods and use sauces, spices, and condiments
Again, it’s very important to eat mostly whole, single-ingredient foods.
The problem is that these foods tend to be more filling than processed junk foods, making it harder to get in enough calories.
Using plenty of spices, sauces, and condiments can help with this. The tastier your food is, the easier it is to eat a lot of it.
Also, try to emphasize energy-dense foods as much as possible. These are foods that contain many calories relative to their weight.
Here are some energy-dense foods that are perfect for gaining weight:
- Nuts: Almonds, walnuts, macadamia nuts, peanuts, etc.
- Dried fruit: Raisins, dates, prunes, and others.
- High-fat dairy: Whole milk, full-fat yogurt, cheese, cream.
- Fats and oils: Extra virgin olive oil and avocado oil.
- Grains: Whole grains like oats and brown rice.
- Meat: Chicken, beef, pork, lamb, etc. Choose fattier cuts.
- Tubers: Potatoes, sweet potatoes, and yams.
- Dark chocolate, avocados, peanut butter, coconut milk, granola, and trail mixes.
Many of these foods are very filling, and sometimes you may need to force yourself to keep eating even if you feel full.
It may be a good idea to avoid eating a ton of vegetables if gaining weight is a priority for you. It simply leaves less room for energy-dense foods.
Eating whole fruit is fine, but try to emphasize fruit that doesn’t require too much chewing, such as bananas.
If you need more suggestions, consider reading this article:
Summary: You can add sauces, spices, and condiments to your foods to make them easier to eat more. Base your diet on energy-dense foods as much as possible.
Lift heavy weights and improve your strength
To make sure that the excess calories go to your muscles instead of just your fat cells, it’s crucial to lift weights.
Go to a gym and lift 2–4 times per week. Lift heavy and try to increase the weights and volume over time.
If you’re completely out of shape or new to training, consider hiring a qualified personal trainer to help you get started.
You may also want to consult with a doctor if you have skeletal problems or any medical issues.
It’s probably best to take it easy on the cardio for now — focus mostly on the weights.
Doing some cardio is fine to improve fitness and well-being, but don’t do so much that you end up burning all the additional calories you’re eating.
Summary: It’s very important to lift heavy weights and improve your strength. This will help you gain muscle mass instead of just fat.
10 more tips to gain weight
To maximize weight gain, it is crucial to both consume a high-calorie diet and engage in intensive strength training.
However, there are additional tactics to expedite weight gain.
To that end, here are 10 more recommendations for gaining weight:
- Avoid drinking water before meals, as this can fill your stomach and make it harder to consume enough calories.
- Try to eat more frequently throughout the day, adding in an extra meal or snack when possible, even before bed.
- Consider drinking whole milk instead of water, as it’s an easy way to get in more high-quality protein and calories.
- If you’re really struggling, try weight gainer shakes which are packed with protein, carbs, and calories.
- Opt for larger plates when possible, as research shows that smaller plates can lead to consuming less food.
- Add cream to your coffee to help increase your calorie intake.
- Consider taking creatine, a muscle-building supplement that can help you gain a few pounds in muscle weight.
- Prioritize getting quality sleep, as it’s essential for muscle growth.
- When eating, start with the calorie-dense and protein-rich foods first, and save the vegetables for last.
- Quit smoking, as smokers tend to weigh less than non-smokers, and quitting often leads to weight gain.
Summary: There are several other things you can do to gain weight even faster. These include drinking milk, using weight gainer shakes, adding cream to your coffee, and eating more often.
Gaining weight can be difficult, but consistency is the key to long-term success
Gaining weight can be a challenging task for many individuals due to their body’s natural setpoint.
This setpoint is the weight at which your body feels most comfortable, and any attempt to increase or decrease it is met with resistance.
Your body regulates hunger levels and metabolic rate to maintain this setpoint, making it difficult to gain or lose weight. When you consume more calories and gain weight, your body responds by decreasing your appetite and increasing your metabolism, which is controlled by your brain and hormones like leptin. Therefore, it’s essential to be patient and consistent with your efforts to change your weight.
It is a marathon, not a sprint, and it may take a significant amount of time, and in some cases, you may need to force yourself to eat despite feeling full.
