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Pre-Exercise Nutrition-What you need to know

The topic of discussion for today’s post is pre-exercise nutrition/fuel.

Are you new to exercising and are not quite certain what you should be eating before a workout? Or maybe you are an avid exerciser looking to improve your performance. Today’s post is for both of you. If you are an athlete or bodybuilder this post is not designed for your needs but a post could be written on this specific topic if enough interest was shown.

People talk about the importance of pre-exercise food and nutrient timing post exercise like it is a life or death situation. Does it leave you dazed and confused? Maybe even feeling like you shouldn’t exercise because you don’t know how to maximize your efforts? Do Not Worry! This is simply not the case. In fact, for the average exerciser, nutrient timing pre-post workout is something you really don’t need to worry about.

Average people with no unique physiological needs can typically consume a nutrient dense meal 1-2 hours before and after exercise to meet the requirements they need. So if nutrient timing isn’t your thing and you feel as though your body runs just fine without this, then feel free to stop reading and know that what you are doing is probably enough. For those of you who want a more in-depth look at pre-exercise nutrition, keep reading.

Just like you put fuel in a car before a trip or check to make sure the battery is fully charged before you use it, the same applies for your body before you exercise. According to Clark (2014 ), “preexercise fuel has five main functions:

  1. It helps prevent hypoglycemia (low blood sugar) and its symptoms of light-headedness, needless fatigue, blurred vision, and indecisiveness…

  2. It helps settle your stomach, absorb some of the gastric juices, and ward off hunger.

  3. It fuels your muscles, with carbohydrate that you eat far enough in advance to get stored as glycogen as well as carbohydrates that you eat within an hour of exercise, which enters the bloodstream and feeds your brain.

  4. It gives you the peace of mind that comes with knowing your body is well fueled.

  5. It helps you exercise harder, so you can burn more calories, if your prime motive for exercise is to lose undesired body fat.”

While each person is different and their bodies may respond differently to pre-exercise food, we will look at some suggested targets.

Pre-exercise Time Gram of Carbohydrates Calories

(per pound of body weight) for 150lb person

4 hours 2(4g/kg) 1200

2 hours 1(2g/kg 600

5-60 minutes 0.5 (1g/kg) 300

Clark 2014

So here is an example to help put the chart into perspective: If you have a morning event such as a road race, swim meet, or spin class that starts at 8am I would start by fueling the night before with a carbohydrate based dinner since you probably will not eat a large meal before you get started. Also make sure to drink plenty of fluids the day before. The morning of, at about 6:30-7am a 150lb person would aim to have a light calorie meal (about 300 calories) dependent upon tolerance. If a larger meal is desired, you should get up earlier. If you cannot tolerate anything in the early mornings, eat your breakfast before you go to bed the night before to boost your glycogen stores.

Examples of light breakfast choices include: yogurt and a banana, a granola bar and a latte (drink plenty of water too), toast with peanut butter, or smoothie *more on pre-exercise caffeine later*

Another example: If you have a 2pm class or afternoon run to look forward to, you have enough time to have a hearty carbohydrate based breakfast (about 1200 calories for 150lb person) that will allow for 4 hours of digestion prior to the event and a light lunch/snack before exercise.

Example for breakfast: French toast, pancakes, cereal, eggs on toast, fresh fruit salad, 100% juice, yogurt, smoothie… * Stick with whole grain low added sugar choices

You will most likely find that pre-exercise fuel has a bit of trial and error. You may find that it also takes a while for your body to be able to comfortably tolerate the food intake as well. Start small and with foods you know will not bother you and slowly increase from there until you reach your desired calorie intake.

What about exercising on an empty stomach to increase fat burning?

You will burn more fat on an empty stomach because carbohydrates will not be readily available to fuel your workout BUT according to Clark (2014), “burning more fat does not always equate to getting leaner.” In order to lose body fat, you will need to create a calorie deficit for the day. This rule applies whether you are burning fat or carbohydrates during your workout. Paoli et al. (2012) found that “you’ll be able to exercise harder, burn more calories, and potentially lose more body fat if you eat a preexercise snack.”

Does food you eat in the hour before exercise even aid your workout or does it just sit in your stomach?

If you are exercising for more than a half an hour, you could consume a small snack just 5 minutes before beginning your workout and that fuel would be used by your body. According to Kerr (2008), “research suggest that eating an energy bar 15 minutes before moderate exercise offers the same energy boost as eating one 60 minutes before exercise.”

Preexercise Caffeine

Lastly, we will take a look at the ever popular preexercise energizer. Many of us consume caffeine first thing in the morning to help wake ourselves up, get ourselves going, and energize our day, but can this same substance help your workout? According to Clark (2014), “the vast majority of studies conclude that caffeine taken an hour before exercise does indeed enhance performance (by about 11 percent) and makes the effort seem easier (by about 6%).” Finding the adequate balance of caffeine for your body will take some work. Don’t think that over caffeinating will just make your workout that much better. When you overconsume caffeine it can lead to undesired pit stops and jitters that will actually decrease performance. Also, Pasman et al. (1995) discovered that well trained cyclist performed adequately well with both 350mg of caffeine and 850mg. So, more doesn’t necessarily equate to better. The suggested target for caffeine is 1.5mg per pound (Doherty & Smith, 2005). This would equate to 225mg for a 150lb person.

Here is a caffeine chart taken from to give you an idea of caffeine content in popular food and drink:

I hope that you have found this both educational and helpful. Also, be on the lookout for my next article that will address fueling during exercise.

What is your favorite way to get in pre-exercise fuel?


Clark, N. (2014). Sports Nutrition Guidebook. Newtown, MA: Human Kinetics

Kerr, K. et al. 2008. Effects of pre-exercise nutrient timing on glucose responses and intermittent exercise performance. Med Sci Sports Exerc 40 ( S77

Paoli, A., K Grimaldi, D. D'Agostino, L. Cenci, T. Moro, A. Bianco, and A. Palma. 2012 Ketogenic diet does not affect strength performance in elite artistic gymnasts. J Int Soc Sports Nutr 9 (1): 34 doi: 10.1186/1500-2783-9-34

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