How to Increase Body Fat Percentage

The best food to gain weight for females and males should be nutrient-dense and high in calories. Being underweight and having a low body fat percentage can be a health concern, so it's important to have a balanced diet. Strength training to build muscle may also be recommended.

Although being lean is healthy, if you are underweight and have extremely low body fat, you may encounter health problems later on. Some people are naturally thin and have a fast metabolism. Regular physical activity, such as in athletes or those who have active jobs, may also cause a low body fat percentage.

If you are on the lean side but still within the normal range of body fat, eating nutrient-rich foods more often can make all the difference.

If you have lost weight suddenly, it's important to talk with your doctor to rule out issues like thyroid problems, diabetes or even cancer, says the American Academy of Family Physicians (AAFP). Stress and depression may also result in weight loss and even cause eating disorders.

When you are underweight, you may not be getting enough calories to fuel your body. Over time, this may lead to malnutrition, says the AAFP. Malnutrition can result in delayed growth and development for teens, as well as weak bones and osteoporosis in people of all ages.

Being underweight can also weaken your immune system, cause hair loss and result in fertility issues, including the absence of menstruation, or amenorrhea, in women.

Your body mass index (BMI) may help determine whether or not your weight is in a healthy range, notes the Centers for Disease Control and Prevention (CDC). You may use the CDC's BMI calculator to get a rough estimate.

For adults who are 20 years of age and older, a BMI below 18.5 may indicate that they're underweight. If your BMI ranges from 18.5 to 24.9, then you are of normal weight. Anything above 25 may indicate that you have overweight or obesity (BMI over 30).

According to the CDC, the correlation between BMI and body fatness is strong, but there are some things to consider. For example, women will often have more body fat than men. Additionally, athletes who have a lot of muscle may have a high BMI but still be healthy.

You can also measure body fat percentage with skinfold calipers or DEXA. Another option is underwater weighing. Skinfold calipers are relatively inexpensive and widely available, but other methods are not as accessible.

Eating nutrient-rich foods and staying in a caloric surplus is a good way to gain weight. Many people who are underweight will feel full faster. Instead of eating three large meals a day, consider eating five to six smaller meals throughout the day, says the Mayo Clinic.

Avoid drinking beverages before a meal as this could decrease your appetite for calorie-rich foods. Consider sipping on a drink during your meal, or even waiting 30 minutes after a meal to drink.

The Mayo Clinic recommends avoiding diet soda, zero-calorie beverages or coffee as they have little nutritional value. You can drink healthy smoothies that contain milk, fresh fruit and protein powder as a snack between meals.

Generally, it's necessary to take in an additional 3,500 calories to gain 1 pound of fat. Therefore, you would need to consume an additional 500 calories a day to gain a pound per week, points out the University of Colorado, Colorado Springs (UCCS).

Eat nutrient-dense foods, including pasta, cereals, whole-grain bread, lean protein sources, nuts and seeds. Here are some nutritious and calorie-dense foods to help you gain weight, as recommended by the UCCS:

• Peanut butter and honey on a bagel or toast.
• Trail mixes with dried fruit and plenty of nuts and seeds.
• Sandwiches, like grilled cheese, tuna or turkey and cheese on whole-grain bread.
  
• Baked potato with chopped veggies, melted cheese or chili.
• Bean burrito: a tortilla filled with refried beans, cheddar cheese and salsa.
• Cheese and crackers with salami.
• Vegetables or pita bread with hummus.
• Nuts, like peanuts, pistachios, almonds or walnuts.
• Sports bar for a snack.
• Hearty soups, such as black bean, lentil, split pea or minestrone.
  
• Chili with meat and beans.
• Opting for starchy vegetables like potatoes, peas, corn and winter squash over low-calorie vegetables like green beans, cauliflower or cucumbers.

Make sure you add plenty of healthy unsaturated fats, including avocados, peanut butter and fatty fish, such as salmon and trout, to your diet. Seeds, nuts and olive or canola oil are a good choice too.

Seek healthy ways to increase your energy intake. For example, you could mix protein powder into milk, as well as shakes, casseroles, mashed potatoes or soups. Consider adding dried fruit or nuts to oatmeal and other whole grains. You can also add wheat germ or oat bran to homemade muffins or bread. Sprinkling shredded cheese and veggies over scrambled eggs is another nutritious option.

Daily snacks like trail mixes or calorie-dense fruit smoothies are a great way to get in some extra calories and increase your body fat percentage. Consider having a bedtime snack, such as peanut butter and jelly sandwiches or a wrap sandwich with turkey and avocado.

Even when you are trying to gain weight, steer clear of high-calorie foods that are full of sugar and fat, such as cakes and doughnuts. These products lack nutritional value and contain nothing but empty calories. It's fine to have an occasional slice of apple pie with ice cream but try to stick to whole foods like Greek yogurt or homemade bran muffins.

​Read more:​ What Foods to Eat to Gain Weight Quickly

Exercise plays a key role in overall health. But if you are trying to gain weight, you should limit high-intensity aerobic exercise and stick to strength training, flexibility exercises and moderate aerobic activity.

If you are trying to increase your body fat due to an eating disorder or another illness, talk to your doctor before starting a workout program. You may need to wait to exercise until it's safe to do so, states the Office on Women's Health.

To build up your strength and muscle mass, incorporate weight training into your routine at least twice a week, recommends the Academy of Nutrition and Dietetics. Include exercises that work all of the major muscle groups, including your quads, hamstrings, gluteal muscles, abdomen, shoulders and arms. Exercises like squats, lunges, push-ups and pull-ups can all build mass and strength.

​Read more:​ Your Ultimate Guide to Gaining Lean Muscle

Combining good nutrition and strength training is essential for bulking up. Make sure you're getting enough calories from protein, carbohydrates and fat and try to consume more calories than you burn.

Be realistic about your body shape and consider how genetics affects your build, says the Academy of Nutrition and Dietetics. If you're thin due to an illness, you'll probably gain weight easier than someone who is naturally thin due to a fast metabolism.

You can make changes through diet and exercise, but long-term drastic changes may be difficult to maintain. What matters most is to keep your weight in a healthy range.