Exercising is great for you. But exercising does not mean that you necessarily need to eat more or consume fancy drinks and energy bars. In fact, if you are exercising casually and less than an hour per day, you may not need any extra calories except a post exercise snack within 30 minutes of your exercise and a healthy, nutritious meal within 1-2 hours. Unfortunately, as primary care doctors, we have seen many patients who come to us because they are frustrated with their inability to lose weight or in fact have gained weight despite exercising. To put things in perspective, an easy aerobic exercise such as running burns about 100 calories per 10 minutes. So, if you go run at an easy to moderate pace for 60 minutes you burn 600 calories. A banana and a tablespoon of peanut butter is all you need to consume within 30 minutes of the activity to replenish some of the carbohydrates and proteins that your muscles need to recover. Similarly, weight training 15-30 minutes 2-3 times a week does not mean that you need to significantly increase your protein intake. And avoid consuming protein bars or powder products, which are full of artificial ingredients and high index sugars. Just have a high protein snack after you are done. Peanut butter, unflavored greek yogurt, or 2 tablespoons of Hemp seed mix is all you need. Also, be sure that you eat a healthy source of protein with all your meals. 

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For the more serious athletes:

However, if you decide to become a more serious athlete and train harder, you do need to increase your caloric intake. Focus on high quality carbohydrates, proteins and fats. Keep your three meals and increase your snacks to increase your food intake. 

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Exercising has a toll on your muscles. Muscles depend on carbohydrates and fats for energy and protein for building new muscle and repairing fatigued muscle after each exercise. So you have to increase the intake of all 3 macronutritients. Do not skimp on calories to lose weight; you will end up injuring yourself and feeling tired and moody (all signs of protein deficiency).

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The timing of what you eat is important. A snack or small meal high in easily digested carbohydrates and proteins within 30 minutes of your exercise is essential for providing your muscles with a source of calories for post-exercise repair and recovery. So, don't go to the gym, hop in the shower, and go off to work with nothing to eat until your next break 4 hours later. If time is sensitive, prepare a snack before you go and take it with you.

 

Here are some examples of post-exercise snacks:

• Banana or apple with 1-2 tablespoons of peanut butter.

• Banana and half cup of berries with 1 cup 2% greek yogurt; you may add 1/2 tablespoon of honey or maple syrup if you wish.

• Homemade shake: a banana, half cup of berries, 1 cup coconut water (high in electrolytes to replenish your sweat), 2 pitted dates, 2 tablespoons of peanut butter. 

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Hydration: 

When you exercise your body generates heat; that heat is then dissipated through breathing vapor and sweating. As a result you lose water, salt, potassium and magnesium (electrolytes in sweat).

If you exercise less than 60-90 minutes, you will replace those electrolytes through your regular meal, but you do have to drink water aggressively to replace your lost fluids.

 

If you exercise more than 90 minutes, then you do need to consume some post-exercise electrolytes with your hydration. One bottle of commercially available sports drinks such as Gatorade immediately after your exercise is all you need for every hour you have exercised. If you want to have a product that is slightly more expensive but is higher quality and more closely resembles the sweat composition, you can buy one of these products online:

• Nuun

• GU Energy 

• Skratch

• Tailwind

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How much should I drink after exercise:

Again, for those exercising for less than an hour, just follow your thirst. See the hydration section for more detail. 

For those exercising for longer periods, you do have to be more attentive and make sure you replace all that sweat within a couple of hours (have you noticed how athletes on TV are always holding a fluid bottle?).  Each person has a different sweat rate, so unfortunately there is no magic formula. You can depend on your urine output, but that means waiting for a couple of hours before you can assess your hydration status. Another more accurate way is to actually measure the amount of water you lose. Don't worry; this is actually quite simple. 

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Sweat rate home test: 

1. Weight yourself naked. 

2. Exercise for one hour (whatever it is that you do regularly). You can drink during this time, but keep track of how much you drink.

3. Come back home and wait for 10-15 minutes (you will continue to sweat for sometime after you are done). 

4. Weigh yourself naked again.

5. The difference in the weight plus any fluid you drank equals the total amount of fluid lost (Babak's test: 4 pounds or about 2L). 

6. Replace this within 1-2 hours of your exercise. 

7. Continue drinking normally (remember, besides exercise you still need to hydrate for your normal daily water intake). 

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