Exercise and Food – What Should You Eat and When?

“Hey, man, you don’t look so hot. You ok?” I asked Marty after we had just finished a gazillion suicide drills on the basketball court. A “suicide” is running, as fast as you can, from the baseline to foul line, back to baseline, to half court, back to baseline, to the other foul line, back to baseline and then from baseline to baseline. This was in college and now a long time ago (sigh) and our coach thought the best way to build a team was to tear it apart with suicide drills after a full practice.

Marty was a junior; seasoned. Used to this. I was a rookie.

Marty looked at me, hands on his knees, nodded his head, then stood up and sort of stumbled over to the bleachers where promptly threw up.

On his way back, wiping his mouth with his forearm, he said,”Shouldn’t have eaten before practice. When I will learn? I’ve done that way too many times.”

I, the freshman, managed to miss dinner before practice not because of any inherent wisdom. Oh no. I got lost on the way to the dining hall. But at least I didn’t throw up.

This issue of when and what to eat before you train is batted around the Internet like a badminton birdie on a windy day. Before, after, not at all, high carb, low carb, protein, no protein, small cats (no – just kidding).

So what gives?

Here’s the thing. It depends on what you’re going to do and why you’re doing it.

If your goal is fat loss, it looks like when you eat matters.

The Science Behind The Strategy

In late 2010, researchers published a new study that compared three groups of healthy men. ((1. Van Proeyen, K., K. Szlufcik, et al. “Training in the fasted state improves glucose tolerance during fat-rich diet.” J Physiol 588(Pt 21): 4289-302.))

All three groups increased their calories by 30% over their usual intake and increased their fat intake by 50%. One group did not exercise and two groups did exercise. One of the exercising groups trained before breakfast and drank water during their sessions while another group ate breakfast and consumed some type of carbohydrate during their sessions (like a sports drink).

At the end of six weeks, the group who ate more calories and did not exercise not only gained weight but had become more insulin resistant (insulin is a hormone that helps move energy into the muscle) – their muscles were less able to use the energy. The group who exercised but did so after a big breakfast also gained weight, although about half as much as the sedentary group, but were still more insulin resistant.

Only the group who exercised in a fasted state gained little to no weight, even though they were eating a lot more calories, and they did not become insulin resistant. One of the study’s authors explained,

“Our current data, indicate that exercise training in the fasted state is more effective than exercise in the carbohydrate-fed state to stimulate glucose tolerance despite a hypercaloric high-fat diet.”

Now, the exercise was strenuous. Four sessions per week. Two sessions of an hour and two of ninety minutes. So, this may not be true if you were, for example, walking around the block barely getting out of breath.

And If Your Goal Is To Add Some Muscle?

But what if your goal is not fat loss but you want to gain some muscle mass or improve your strength and muscle tone? Then what?

Well, there aren’t as many studies on gaining muscle mass as there are on losing body fat. But there are a few that provide some direction.

To add weight, whether it’s muscle or not, you have to eat more in general which also adds the risk of gaining fat if you eat too much. But, it appears that what you eat is important: protein.

Now, the question is, how much protein do you need and from what source?

Researchers from California State University analyzed three groups of men to determine if just extra calories or extra calories in the form of protein would increase muscle mass ((Rozenek, R., P. Ward, et al. (2002). “Effects of high-calorie supplements on body composition and muscular strength following resistance training.” J Sports Med Phys Fitness 42(3): 340-7.))

One group added a protein supplement to their normal diet while the other group added a carbohydrate supplement. Both groups then exercised using weights, four days per week between sixty and ninety minutes per session.

At the end of eight weeks, the group that consumed the carbohydrate supplement increased their lean mass slightly more than the protein supplement group but the protein group increased their strength by 23% compared to 14% in the carbohydrate group.

So, if you want to add muscle size and strength, you need protein – about 1 to 1.25 grams per pound of lean body mass.

That means if you weigh 200 lbs with 30% fat, your lean mass is 140 lbs (Body weight – fat mass = lean body mass). So, in that case about 140 grams of protein a day.

But, what in what form? I think you’ll agree that when you consider that a chicken breast the size of your palm is about 20 grams, eating seven chicken breasts a days is at the very least a lofty goal.

Most people use a supplement – a protein drink or smoothie. And once again, science shows us which type of protein supplement gives you the most bang for your buck.

Some researchers from Canada compared the effects of whey or soy supplementation on a group of men and women. In turns out that whey protein supplements delivered better results in increasing lean mass and strength than a soy protein supplement ((Candow, D. G., N. C. Burke, et al. (2006). “Effect of whey and soy protein supplementation combined with resistance training in young adults.” Int J Sport Nutr Exerc Metab 16(3): 233-44))

What About “Carbo Loading”?

“Carbo loading” is an eating strategy sometimes used by endurance athletes to help them avoid “hitting the wall” or running out of energy.

When you exercise, you use both carbohydrate and fat for energy. And because fat must be converted through an enzyme process in order to be used for energy, you need carbohydrate to to supply some fuel while your body is converting the fat. When your carbohydrate levels get too low, you can’t convert fat fast enough to meet the demand and you run out of fuel or hit the wall.

Athletes discovered that if they eat a lot of carbohydrate, and mostly refined carbohydrate like pasta and bread, a certain amount of time before, for example, a marathon, they could avoid the problem of hitting the wall. ((Hargreaves, M., J. A. Hawley, et al. (2004). “Pre-exercise carbohydrate and fat ingestion: effects on metabolism and performance.” J Sports Sci 22(1): 31-38.))

But your exercise intensity and duration have a large impact on how your body uses energy. For example, if you run a marathon at 50% of your MaxVO2 (and this would be about 50% of your maximum heart rate), because the intensity is low, your body will likely have enough energy to manage the race. But if you boost your intensity even just to 60-70%, you’ll have a good chance of hitting the wall.

So, in other words, you can run/walk a marathon and not need to “carbo load” because the intensity is low enough your body will be able to process fat for fuel (you can learn more about how much carbohydrate you need by using this calculator). The more fit you are, the faster you access your fat stores and fat is a much better source of energy than carbohydrate for long duration exercise.

The science of “carbo loading” is relatively clear but when it comes to ingesting carbohydrate before exercise, in general, the topic is controversial.

There have been studies that show ingesting carbohydrate within 60 minutes prior to exercise improves, has no effect, and has a detrimental effect on performance. This may be due to individual variability when it comes to digesting and using carbs as well as the intensity and duration of the exercise. This is a situation where you’ll have to experiment and find what’s right for you; what makes you feel good and sustains your energy through the activity.

Summary

• If your goal is to lower body fat, use a strenuous form of exercise before breakfast and then consume a protein heavy meal.
• If your goal is to increase your lean body mass, add a whey protein supplement up to three times per day with one of those occurring after a training session.
  • Aim for 1 to 1.25 grams of protein per pound of lean body mass.
• If you will be exercising at a moderate to high intensity for 90 minutes or more, “carbo loading” will help you perform better and feel better.
• If you will be exercising for 60 minutes or more, increase the amount of carbohydrate ingestion within an hour prior to the activity and adjust as needed based on your body’s response.

What’s your strategy when it comes to training and food?