While 5 pounds of muscle and 5 pounds of fat weigh the same, they can look quite different and have different health effects. Muscle is not factored into your BMI, but it is factored into your body fat percentage.

Not all pounds are created equal. In fact, your total body weight isn’t a clear indicator of how you look or what health risks you may face.

Two different people who weigh the same amount can look very different when one has a high percentage of fat and the other has a high percentage of muscle.

An extra 20 pounds of fat may give you a softer, less toned appearance. But an extra 20 pounds of muscle will look firm and sculpted.

Muscle also serves a different function than fat. Fat helps insulate the body and trap in body heat. Muscle boosts your metabolism. This means the more muscle you have, the more calories you burn when you’re at rest.

Researchers have found that people with a higher percentage of body fat have a higher overall death rate, regardless of their weight or body mass index (BMI).

Fat increases your chance for developing conditions such as:

This means that even people with a low body weight but a poor muscle-to-fat ratio are at higher risk for obesity-related conditions.

Keeping your body fat percentage low is important for preventing obesity-related conditions.

That doesn’t mean you have to build an excessive amount of muscle. While muscle is never unhealthy and you can’t have too much of it, it’s fine to strive for more reasonable goals.

The recommended body fat percentages vary a bit. The following recommendations, courtesy of Vanderbilt University, are based on gender and age and come from the American College of Sports Medicine guidelines:

AgeFemale (% body fat)Male (% body fat)
20-2916%–24%7%–17%
30-3917%–25%12%–21%
40-4919%–28%14%–23%
50-5922%–31%16%–24%
60+22%–33%17%–25%

These can further be classified by averages seen among athletes and people who are fit, average, or have obesity:

ClassificationFemale (% body fat)Male (% body fat)
Athletes14%–20%6%–13%
Fit people21%–24%14%–17%
Average people25%–31%18%–24%
People with obesity32% and higher25% and higher

Testing your body fat composition is a bit complicated.

Some gyms and doctors’ offices provide high-tech testing devices that use bioelectric impedance (BIA) to detect fat cells. There are also new home scales that use technology to estimate body fat percentage.

These measuring tools can sometimes be imprecise. Outside factors, such as how much water you’ve been drinking, can affect the results these tools provide.

Muscle mass isn’t related to your BMI. Your weight and height determine your BMI, not your body composition. Research shows, however, that BMI is moderately related to body fat measurements.

Furthermore, research indicates that BMI is as accurate a predictor of various disease outcomes — such as diabetes and hypertension — as more direct measures of body composition.

If you want to build some lean muscle or bulk up a bit, try these tips:

  • Practice strength training exercises 3 to 4 days per week.
  • At home, take advantage of your own body weight with pushups, pullups, and squats.
  • Incorporate strength training into your cardio work with high-intensity interval training (HIIT) routines.
  • Don’t be afraid to push yourself with increasingly heavier free weights.
  • Consider doing a session with a personal trainer who can show you how to lift safely and effectively.
  • Consider recreational activities that help you build muscle, like climbing, yoga, or biking.
  • Eat a high protein diet to fuel your muscle development. If you’re trying to bulk up, increase your daily calories intake with lean proteins like chicken and fish.

Weight loss is about more than just building muscle. Here are some tips to help you lose weight:

  • Eat a balanced diet full of nutritious foods. Losing weight isn’t just about cutting calories. It’s also about eating the right calories. Increase your intake of fruit, vegetables, and lean protein to help you feel full longer. Reduce or eliminate empty calories like sugary coffee or soft drinks and heavily processed snack foods like chips.
  • Avoid undereating. To lose weight, you want to cut calories. But if you cut too many calories, your body can go into starvation mode. This can slow down your metabolism and sabotage your weight loss goals.
  • Speaking of goals, set realistic ones. Unless your doctor has recommended differently, aim to lose no more than one to two pounds a week.
  • Exercise every day. Exercise doesn’t have to always include an intense sweat session. Get off the bus a couple stops early to add in some extra steps or take the stairs. If you watch television at night, try lifting weights during commercials instead of fast-forwarding past them or grabbing a snack.
  • Avoid the scale. Sometimes staying off the scale can help keep you on track. That’s because you won’t see those days when extra water weight makes it look like you’ve gained weight. Instead, focus on how your clothing fits. Are your pants less snug around the waist and thighs?
  • Work with a nutritionist. If you’ve been eating healthy and exercising but not losing weight, consider working with a nutritionist. They can help tweak your diet and portion sizes, which may help kick-start your weight loss.
  • Switch it up. If you always eat the same things and do the same workout, consider switching it up. That can help you avoid weight loss plateaus and keep you from getting bored.
  • Talk to a doctor. If you’re concerned about your weight, consider talking to your doctor. They can help you set realistic goals and create a weight loss plan.

If you have a dependable exercise routine and healthy eating habits, don’t worry so much about the scale.

If you’ve recently upped your game and are concerned that you aren’t losing weight fast enough, try a different unit of measurement.

If your pants feel loose around the waist and your T-shirts feel tight around the arms, then you’re probably losing body fat and building muscle.