The majority of Americans are overweight, but some people have the opposite issue. They weigh too little instead of too much. Being underweight carries similar risks to being overweight, so it’s essential to take steps to reach and maintain a healthy weight.
We created this guide for informational purposes only. You should always contact your doctor or a dietician before you make any changes to your normal diet.
What is Underweight?
Your Body Mass Index (BMI) expresses how healthy your weight is, depending on your height and other potential factors. You’re considered underweight if your BMI is less than 18.5. The National Institute of Health has a healthy weight calculator to make it easier to determine if you’re at an appropriate weight.
If you’re underweight, it might be from limited nutrition or an underlying condition. Underweight people can face a few health problems if they don’t take steps to correct any underlying issues. These health issues include:
- A weaker immune system. You’re more likely to fall ill if you’re underweight.
- Nutrient deficiencies that may evolve into more severe conditions, such as osteoporosis or anemia.
- Women may experience fertility issues if they’re underweight.
Common Reasons for Low Body Weight
Bodyweight fluctuations are normal. However, if you lose more than 5 percent of your weight over 6 to 12 months with no clear explanation, it’s best to speak with your doctor about possible causes and what you might need to do to regain the weight.
Weight loss is normal after a recent stressful event, such as the loss of a loved one or a significant lifestyle change. Once you’ve had time to adjust to the change and are feeling happier, your weight should return to normal. You may want to consider psychotherapy to make the transition smoother.
Other causes of unintentional weight loss include:
- An overactive thyroid or mishandled treatment of an underactive thyroid
- Dental issues, such as chipped or cracked teeth, new orthodontics, or mouth ulcers
- Dysphagia, or swallowing difficulties
- Gut problems such as stomach ulcers, Celiac’s disease, Crohn’s disease, or ulcerative colitis
- Dementia patients who can’t communicate their hunger needs
- Inflammatory conditions such as arthritis
- Heart disease
- Undiagnosed diabetes
Not All Fats Are Equal
There’s monounsaturated and polyunsaturated fats, saturated fats, and trans fats. You’ll find healthy monounsaturated and polyunsaturated fats in fish, vegetables, nuts, and seeds, not junk food.
Monounsaturated and Polyunsaturated Fats
These are the beneficial fats everyone needs to consume. Monounsaturated and polyunsaturated fats differ from each other in their carbon chain structures.
Monounsaturated fats are in various oils (olive oil, peanut oil, canola oil, and certain safflower and sunflower oils), avocados, and nuts. A 1960s study conducted in the Mediterranean region was the first to link olive oil and its monounsaturated fats with reduced heart disease risk.
Polyunsaturated fats are in other oils (corn oil, safflower oil, sunflower oil, walnut oil, soybean oil, canola oil), various fish (salmon, mackerel, sardines), walnuts, and flaxseeds. Eating polyunsaturated fats instead of saturated fats can lower harmful cholesterol and triglycerides.
Saturated fats are a common diet staple. You’ll find them in red meat, whole milk products, cheese, coconut oil, and more. They’re not quite a “good” fat, but you don’t have to entirely cut them out of your diet.
Eating a lot of saturated fats can increase your total cholesterol and block your arteries. Many experts recommend limiting saturated fats to under 10 percent of your daily calorie intake.
If there are any fats you should avoid completely, the answer is trans fats. They have no safe levels of consumption and offer no health benefits. Ingesting trans fats can increase your risk of heart disease, stroke, diabetes, and other chronic medical conditions.
Trans fats are banned in the United States and other countries.
Healthy Ways to Gain Weight
Safe weight gain isn’t just about choosing high-fat foods. That kind of diet will likely leave you with a lot of belly fat, rather than the mix of muscle weight and subcutaneous fat you want. As we mentioned earlier, some fats are healthier than others. It’s better if your food intake incorporates “good” fatty foods instead of just junk food.
Foods you should focus on include whole-grain products, lean proteins, nuts and seeds, fruits and vegetables, and dairy. An occasional treat is okay, but you want to be careful not to overeat sugar and saturated fat.
The secret to gaining weight is to eat more calories than your body can burn. A calorie calculator can help you determine how much you need to eat to maintain your weight. Add a few hundred more calories, about 300 to 500, to safely gain weight.
You should discuss with your doctor safe ways to gain weight before you make any major lifestyle changes. We’ll discuss some of the more common methods.
Eating more meals can be a simple path toward weight gain. Instead of three regular meals, eat five to six smaller meals. You can also “fill out” a meal with some extras. Sprinkle some cheese on eggs or vegetables, or bulk up a stew with some meat or dried milk.
In between meals, you can snack on nuts, fruits, avocados, and simple sandwiches.
You may want to watch what and when you drink. Occasionally, people find their appetites are suppressed if they drink before a meal. It might be better to drink during or after a meal instead.
On a related note, you shouldn’t drink too much soda, coffee, and other beverages with few nutrients and calories. Try a smoothie or even a liquid meal replacement instead.
It’s also a good idea to avoid water close to bedtime. Otherwise, you might experience sleep interruptions.
Eating and drinking isn’t the only way to gain weight. You can also try exercising to bulk up your muscle mass. Focusing on strength and resistance training, as well as typical aerobic activities, can further help you build up your muscles. Exercising can also increase your appetite.
Frequently Asked Questions
One of the simplest ways to improve your appetite is to watch what and when you drink. Some people find they feel less hungry if they drink shortly before they eat, even if it's just water. You might want to try rehydrating yourself about half an hour after you eat.
You can also increase your daily number of meals. Instead of the usual three, you can have five or six small meals. Plus, try garnishing your meals with extra protein. Plenty of meals taste great with added cheese, and you can thicken a stew or soup with some dried milk
Some drugs and supplements are designed to help you gain weight. Some are over the counter products and unregulated. We advise caution with these pills and supplements, as few are backed by scientific evidence.
The other option is prescription pills, which may be recommended for patients recovering from an illness that involved weight loss. Your doctor can help you decide if a prescription is right for you.
It’s not advisable to try and survive on just one food group. We need variance in our diet to acquire all the nutrients we need. Eating only vegetables would deprive us of the fats and proteins we need to survive.
It’s difficult to say what’s the best fruit to eat, especially since scientists are still studying their benefits. Pineapple is a good choice since one cup provides your daily recommended dose of vitamin C. Plus, pineapple has anti-inflammatory properties.
There’s also grapefruit, which reduces insulin levels and resistance and decreases the chances of urinary stones. Finally, avocados are full of healthy fats, potassium, fiber, and magnesium. We recommend incorporating a variety of fruits into your diet.
Three foods you might better off without include:
- Sugary drinks. Not only can these drinks drastically increase your daily sugar intake, but you might not realize how many calories you’re ingesting when you drink. And because their liquid calories don’t register with your body the way solid food calories do, it’s easy to overindulge.
- Sugar-filled breakfast cereals. Some of the more popular cereals can be as unhealthy as a bowl of candy.
- High-calorie coffee drinks. A simple coffee drink can be good for you. For example, many athletes enjoy coffee before a workout. However, too much cream, sugar, and syrup can negate the benefits that plain coffee offers.
Did We Help?
It’s important to understand that healthy weight gains may not be immediate. You may require a few days or even weeks to bulk up and reach a healthy weight. Remember that your weight shouldn’t just come from junk food but wholesome meals that build up your muscle mass and subcutaneous fat.
This article is for informational purposes and should not replace advice from your doctor or other medical professional.