If you want to reach your fitness goals, what you eat and when is crucial. And while we know that eating after a workout, especially après a particularly intense one, whether we should eat before a workout is less clear.

“Pre-workout nutrition is largely personalized,” says Chad M. Kerksick, Ph.D., associate professor of exercise science and director of Exercise and Performance Nutrition Laboratory (EPNL) at Lindenwood University in Missouri. He suggests asking yourself: Do you really know why you’re drinking that protein shake?

Read on to find out how your body, goals, protein and supplements can inform how you fuel your workouts and when.

Is there a window when I should eat before working out?

Generally, it’s best not to eat right before a workout. “During the workout, your muscles are trying to work, but your digestive system is simultaneously trying to digest the food in your stomach,” says Riley Thornton, RDN, a dietitian and wellness specialist at the University of Alabama at Birmingham. “If you are doing cardio such as running, dancing or using the elliptical, that snack or meal right before your workout may alter your performance and cause GI distress.”

Ideally, it’s best to eat about one to three hours before your workout, Thornton says. But timing your pre-workout snack will depend on your schedule and your knowledge of your body’s ability to exercise with food in your stomach. She suggests the following pre-workout nutrition strategies depending on when you’re working out:

  • Your workout is in the morning: Thornton says to consider eating 30 minutes to an hour before training. This could be a medium banana, a low-fat granola bar or Greek yogurt. Eat a breakfast afterward that consists of carbohydrates and protein, such as a smoothie made from cottage cheese and fruit, oatmeal with peanut butter or a hard-boiled egg with two pieces of toast.
  • Your workout is right after work: If you had a late lunch—say around 2 p.m.—that consists of carbs and protein, you should be adequately fueled for moderate- to vigorous-intensity aerobic exercise. However, if you feel low on energy, consider a small carb-filled snack 30 minutes before you exercise. Then time your dinner as a post-workout meal, eating between 30 minutes and two hours afterward. Make protein the centerpiece of the meal (at least 25 to 35 grams).
  • Your workout is in the evening: If you eat an early dinner, ensure it includes carbs and some protein. To refuel and rehydrate, drink 8 ounces of chocolate milk 15 to 30 minutes after your activity, or if your goal is to build muscle, this is a good time to consume a nutrient-dense protein shake—such as Optimum Nutrition Gold Standard 100% Whey Protein or Isopure Protein Powder.

Will consuming protein before weight training help me build more muscle?

“It isn’t the right mindset to think that protein will or won’t do anything for you if you are a particular type of athlete. There is mixed evidence about whether you should have protein before or after a workout,” Kerksick says. “Protein can be beneficial for all athletes.”

“Incorporating foods with protein is important to prime your muscles with amino acids needed for your muscles to repair and rebuild, especially for weight-training programs,” Thornton says. But it isn’t the only thing fueling your muscles. “Carbohydrates provide you the energy to perform and your muscles the capacity to do so,” she adds. Some simple pre-workout snacks include a blend of carbs and protein such as Greek yogurt with fruit or toast or a banana with peanut butter.

How much protein should I consume pre-workout?

How much and what type of protein you consume is extremely personal. “People need to understand their bodies, as well as what their goals are,”  Kerksick says. Besides understanding the amount of time you have to digest your food before a workout, you should look ahead to the workout itself and how intense it will be. What you eat, how long before and the intensity of the workout could add up to either a kick-ass workout or GI troubles that derail your training.

This might be why Kerksick suggests thinking about your protein allowance in daily terms instead of per meal. “You want to eat enough protein day in and day out,” he says. That is 1.2 to 1.4 grams per kilogram (0.6 to 0.7 grams per pound) for someone who is exercising a couple of times per week. However, an individual who is completing four to five intense resistance-training and cardio workouts per week might want to increase his or her protein intake to 1.6 to 1.8 grams per kilogram (0.7 to 0.85 grams per pound) for someone who is exercising more than three times a week. For example, a 160-pound person who is training four times a week should consume 116 to 131 grams of protein per day. Definitely not an amount that you can pound down, so aim to deliver enough protein throughout the day.

“Consuming a healthful diet throughout the day with adequate protein is the best way to ensure that muscles are prepared to rebuild and repair muscles after vigorous exercise,” Thornton says.

Are there supplements I should take before working out? If so, which ones and why?

Both Kerksick and Thornton point out that supplements and protein powders cannot compensate for a diet lacking in nutrients that bodies need. However, depending on your goals, some supplements can help you achieve them. Two supplements that have good safety profiles are creatine and beta-alanine.

Creatine. Numerous studies have shown that creatine increases muscular strength and power and lean muscle mass. After supplementing, muscle cells are more resistant to fatigue and consequently can contract more forcefully. Put simply, when taking creatine, you might eke out 10 reps with a weight that you can normally only lift for eight reps.

Beta-alanine. This supplement has been shown to improve strength, anaerobic endurance and anaerobic power. This means it can allow you to exercise at a high intensity for a longer period, which can make your workouts much more productive. More productive workouts mean that you may reach your goals faster. Recommended doses are a minimum of 3 grams per day and up to 6 grams per day.

One thing to keep in mind regarding creatine and beta-alanine is they need to be taken consistently to work, according to Kerksick. Luckily, you can stock up on all your pre-workout energy supplements at the gym. Optimum Nutrition Essential Amino Energy, which contains beta-alanine, and Cellucor C4, which has creatine nitrate and beta-alanine, are popular options among athletes and fitness enthusiasts alike.

Will having a cup of coffee affect my workout if I drink it beforehand?

“Coffee may generate some effects in your workout when consumed beforehand, but timing is important and being mindful of your own body’s tolerance is key,” Thornton says. Research has shown that consuming caffeine whether as a sports drink or coffee before a workout may lessen your perceived rate of exertion, thus allowing you to exercise at a higher intensity, according to Kerksick. You may find that you also can get in a few more reps after consuming caffeine before your workout. However, its ability to increase your strength has not consistently been documented.

One thing to keep in mind about caffeine is how your body reacts to it. If you’re a regular caffeine drinker, you may experience less of a laxative and dehydration effect from it. If you don’t, GI distress might be a concern.

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