Humans need a certain amount of body fat to maintain basic functions.

However, a higher body fat percentage can negatively affect performance in athletes.

While there's no shortage of weight loss advice on the internet, athletes need to approach weight loss with care.

Failing to do so can negatively affect training and lead to loss of precious muscle.

An inappropriate diet can also make the difference between winning the race and not even qualifying.

These 9 weight loss tips are specifically for athletes. They use the latest science-based recommendations to lower body fat while maintaining sports performance.

It's very difficult to decrease body fat and reach peak fitness at the same time.

That's because to lose fat, you need to eat fewer calories. This can make training feel more difficult and prevent you from performing at your best.

For this reason, it's best to lose fat in the off-season, when you are not about to compete. If that's not possible, the next best option is to lose fat during less-intense training periods.

Another reason to attempt fat loss in the off-season is that it will give you more time to reach your body fat percentage goal.

This is good because losing weight at a slower rate decreases the likelihood of muscle loss. It also seems to support better sports performance (1).

Most research agrees that weight loss of 1 lb (0.5 kg) per week is ideal (1, 2, 3).

Bottom Line: Lose weight in the off-season at a rate of 1 lb (0.5 kg) per week or less. This will help minimize muscle loss while supporting sports performance.

If you cut calories too drastically, your nutrient intake may not support proper training and recovery.

This can increase the risk of injury, illness and over-training syndrome (2).

The latest sports nutrition guidelines also warn against eating too few calories and reaching a dangerously low body fat percentage.

That's because both can disrupt reproductive function and diminish bone health (2).

The lowest safe recommended body fat percentage is 5% in males and 12% in females. However, these levels are not necessarily best for all athletes, so discuss what's best for you with your coach and sports dietitian (4).

Cutting calories too quickly can also negatively affect hormones and metabolism (5).

To decrease body fat, athletes should eat about 300–500 fewer calories per day but avoid eating less than 13.5 calories per lb (30 kcal/kg) of fat-free mass per day (2, 3).

If you don't know how much fat-free mass you have, get your body composition estimated with either a skin fold test or bio-electrical impedance analysis (BIA).

You can also get your body composition measured by dual-energy X-ray absorptiometry (DXA) or underwater weighing. These are more accurate, but also tend to be more expensive and harder to come by.

Bottom Line: Crash diets can increase your risk of illness, injury and negatively affect your training and recovery. Therefore, avoid cutting your calorie intake by more than 300–500 calories per day.

Low-carb diets providing less than 35–40% of calories from carbs seem very effective at promoting fat loss (6, 7, 8).

However, restricting carbs too dramatically is not always best for athletes. That's because it can negatively affect training and sports performance (2, 3, 9, 10).

Aim for a carb intake that's 40% of your daily calories to maximize fat loss. However, consume no less than 1.4–1.8 grams of carbs per lb (3–4 g/kg) each day (2, 11).

Cutting out added sugars is the healthiest way to reduce your total carb intake.

To do so, check labels and minimize foods that contain added glucose, sucrose, fructose or any other sugars ending in -ose.

Also, avoid cane juice, dextrin, maltodextrin, barley malt, caramel, fruit juice concentrate, fruit juice crystals and any type of syrup.

Instead, increase your intake of vegetables high in fiber. These will help keep you fuller for longer, making you feel more satisfied (12, 13, 14).

Bottom Line: Eating less sugar and more fiber can help you reach your body fat goals. Athletes should aim to eat no less than 1.4–1.8 grams of carbs per lb (3–4 g/kg) each day.

Protein helps with fat loss in several ways.

To begin with, high-protein diets increase feelings of fullness and the number of calories burned during digestion.

High-protein diets also help prevent muscle loss during periods of weight loss, including in well-trained athletes (5, 15).

In fact, several studies show that eating two to three times more protein per day can help athletes retain more muscle while losing fat (9, 16, 17).

Therefore, athletes restricting their calories to lose weight should eat between 0.8–1.2 grams of protein per lb (1.8–2.7 g/kg) of body weight per day (2, 3, 18).

That being said, there's no advantage to exceeding these recommendations.

Consuming more than these amounts can displace other important nutrients, such as carbs, from your diet. This can limit your ability to train and maintain good sports performance (2, 3, 9, 19).

Bottom Line: Higher protein intakes help limit the amount of muscle lost during a period of weight loss. Athletes should aim to consume 0.8–1.2 g/lb (1.8–2.7 g/kg) of protein each day.

In addition to eating more protein, athletes can benefit from spreading their intake throughout the day (20).

In fact, 20–30 grams of protein per meal seems sufficient to stimulate muscles to produce protein for the following 2–3 hours.

This is why many scientists believe that a protein-rich meal or snack should ideally be consumed every 3 hours (3, 21).

Interestingly, studies in athletes show that spreading 80 grams of protein over four equal meals stimulates muscle protein production more than splitting it over two larger meals or eight smaller ones (22, 23).

A 2-week weight loss study in boxers also found that those who spread their daily calorie allowance over six meals instead of two lost 46% less muscle mass (24).

Eating a snack containing 40 grams of protein immediately before bedtime can also increase muscle protein synthesis during the night. This may help prevent some of the muscle loss expected during sleep (25).

However, more research in athletes is needed to draw strong conclusions.

Bottom Line: Eating 20–30 grams of protein about every 3 hours, including right before bed, may help maintain muscle mass during weight loss.

Eating the right foods after training or competing is very important for athletes, especially when trying to lose body fat.

Proper refueling is especially important for days with two training sessions or when there are less than eight hours of recovery time between workouts and events (2).

Athletes following carb-restricted diets should aim to consume between 0.5–0.7 grams of carbs per lb (1–1.5 g/kg) of body weight as soon as possible after a training session (2, 3, 11).

Adding 20–25 grams of protein can further speed up recovery and promote protein production in your muscles (2).

Bottom Line: Consuming a good amount of carbs and protein immediately after training can help maintain your sports performance during weight loss.

Individuals attempting to lose weight are often at risk of losing some muscle in addition to fat. Athletes are no exception.

Some muscle loss can be prevented by eating a sufficient amount of protein and avoiding crash diets. However, lifting weights can also help you hold onto muscle (3).

Research shows that both protein intake and strength-training exercises stimulate muscle protein synthesis. What's more, combining the two seems to produce the greatest effect (26).

Nevertheless, make sure to speak to your coach before adding any extra workouts to your schedule. This will reduce the risk of over-training or injuries.

Bottom Line: Strength-training exercises can help prevent the muscle loss often experienced during a period of weight loss.

Once you've reached your body fat percentage goal, it's tempting to quickly start eating more.

However, this may not be the most effective way to maintain your results.

That's because your body can adapt to a restricted calorie intake by adjusting your metabolism and hormone levels.

Researchers believe these adaptations can persist for some time after you re-increase your calorie intake and cause you to quickly regain the lost fat (5).

A good alternative may be to increase your calories gradually.

This may help restore your hormone levels and metabolism better, minimizing the weight regain (5).

Bottom Line: Increasing your calorie intake gradually after a period of weight loss may help minimize weight regain.

Although weight loss is a widely researched topic, the amount of scientific studies performed on athletes is limited.

Nevertheless, some of the strategies scientifically proven to help non-athletes lose body fat may also benefit athletes.

Therefore, you may find it helpful to:

  • Record your portions: Measuring your portions and keeping track of what you eat is scientifically proven to help you get better results (27).
  • Drink enough fluids: Drinking liquids before a meal, whether it's soup or water, can help you easily consume up to 22% fewer calories at the meal (28, 29).
  • Eat slowly: Slow eaters tend to eat less and feel fuller than fast eaters. Eating slowly can help you decrease your calorie intake without feeling hungry. For the best results, aim to take at least 20 minutes per meal (30, 31).
  • Avoid alcohol: Alcohol is a source of empty calories. What's more, alcohol can prevent athletes from properly refueling after exercise, which can negatively affect future performance (32, 33, 34).
  • Get enough sleep: Research shows that too little sleep can increase hunger and appetite by 24%. Sleep also plays an important role in athletic performance, so make sure you get enough (35, 36).
  • Reduce your stress: Having high levels of stress increases cortisol levels, which promotes food cravings and the drive to eat. Mental and physical stress can also prevent proper recovery (37, 38).
Bottom Line: Stress, sleep, hydration and alcohol all affect weight loss. Eating slowly and keeping a food journal can also help you lose weight.

Fat loss can be beneficial, but athletes must do it in a way that doesn't negatively affect their sports performance or health.

Those who want to reduce their body fat levels should aim to do so during the off-season, by following a well-planned diet and the lifestyle changes described above.

Finally, remember that lower body fat is not always better. Athletes should discuss any weight loss goals or strategies with their coach or sports dietitian.