Food to Fuel Exercise
To begin, consider why you are engaging in physical activity – are you trying to help your body adapt and improve? Or are you moving to pursue weight loss? This distinction matters. One positions food and the body as a threat. The other as an ally.
“Training” is pursued in the spirit of adaptation – doing the types and amount of movement and nutrition to help the body move easier, farther, and/or faster. Training involves tough days, easy days, and rest with thoughtful progressions and the body’s challenge/recovery. It helps the heart beat more efficiently, lungs exchange oxygen, and muscles fire more reliably. It’s about improving movement and honoring/respecting the shape needed to perform that movement.
Let’s remember the “point” of training
When you train, you are essentially trying to accomplish 2 things :
- STRENGTH – be able to resist more force. Whether that means picking up your grandchild or a small truck, strength training is about creating muscle and allowing the body to practice key movements in a controlled setting
- ENDURANCE – be able to move farther with less effort. Whether that’s being able to walk down the hall or complete an Ironman triathlon, you are strengthening your heart and lungs which thereby increases the amount of oxygen they can take in and circulate to the body, with less effort. It also creates more oxygen receptors in the muscles.
- Challenge yourself (consistently). When you challenge (not destroy) yourself, you cause you cause little bits of microscopic damage to the part of the muscle that contracted (heart, lungs, biceps, etc). The harder the work (within reason), the more damage that occurs, and the greater the repair/adaptation – thereby building muscle. The body does a lot of this within the first hour of exercise and then continues for the next 24-48 hours. We refer to this time period as “recovery.” If you give your body energy before a workout (food = energy), you are able to work at a higher level thereby increasing the challenge.
- Help your body repair. Nutrition is helpful with this repair process. When you eat or drink protein (paired with a little carbohydrate and antioxidants) within an hour of the damage, the body does a better job repairing the damage and builds better/stronger muscle. This allows you to workout harder the next time, causing more damage…then repair/adaptation….and the process continues. If you give your body energy (food = energy) after a workout, it has more tools to repair the damage. Not eating after a workout is like asking a builder to fix a roof without a hammer or nail gun. Sure they can use other tools and “get by”, but the process will take longer and likely not be as strong compared to if they had the right tools. I’ll cover eating after movement in another blog post.
Question: Do I always need fuel before movement?
Pretty much. Depending on how long you plan to move and when you ate last, your body still needs fuel to challenge itself. The portion varies greatly depending on your goals and training schedule. Check out the chart below for a little general guidance:
Question: But I’m not an athlete…do the rules still apply?
I would argue anyone who moves intentionally or with a health goal in mind is an athlete. You may not be competing, but if you’re trying to challenge and improve your body, it needs fuel to work it’s best.
Question: Won’t I burn more calories (or fat) if I go into a workout fasted?
I know, it seems counter intuitive to eat if you are trying to lose weight. Here’s the deal, even if you’re trying to make your body smaller, it’s often because you want some of the same training outcomes – increased muscle (metabolism) and the ability to do cardio longer and burn more calories. If you put in minimal fuel because you’re scared of calories, workouts not only feel terrible (making you less likely to return for a 2nd round), it also compromises how hard you can work and the results you see.
Additionally, going into workouts under-fueled because you are restricting what you eat means that your glucose stores are low. If glucose is low, the body is much likely to pull amino acids from muscle as fuel. If you are losing muscle, you are doing the opposite of training or health…
Question: What kind of fuel is best?
Question: You still haven’t answered my question, WHAT AM I SUPPOSED TO EAT?
If you haven’t come to the conclusion already based upon my lengthy explanation, your body works best on glucose during workouts. Glucose comes from carbohydrates (to understand “what” carbs are, check out this blog post).
Exactly what and how much you should eat depends on when you’re working out relative to your last meal / snack.
Most exercise (strength and cardio) uses glucose as fuel in one way or another. Glucose (aka blood sugar) comes from starch (rice, potato, pasta, crackers, cereal, flour, bread) and sugar. The body also has stores of glucose called glycogen that it will use if it runs out of glucose. The body prefers to have glucose readily available rather than breaking down glycogen for fuel.
Note: The body also uses fat as fuel at lower intensities. BUT that doesn’t mean you need to or should workout longer or slower in order to lose weight / burn fat. Changing your workout duration and intensity just to change fuel sources will either leave you under or over challenged. Do what you love and challenge your body – it will adapt as necessary.
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Situation based fueling
If you workout in the afternoon…you likely had lunch 2-3 hours before. Technically whatever you ate at lunch should be enough to fuel an hour workout. But you may want to add a quick fuel source if…
- You didn’t have starch at lunch (eg, you just ate vegetables + meat)
- You skipped lunch OR ate lunch >3 hours before your workout
- Your workout is more than an hour
If you workout after dinner…If you are a late night warrior, it can be tricky to balance food and exercise. Eating a boat load of veggies and meat before a workout is a recipe for misery. Additionally, saving dinner for after the workout may feel tricky. You may consider…
- Break dinner into 2 instances – eat the starch portion and a little meat before. Eat the remaining starch, meat, and veggies after
- Eat an earlier dinner and a refuel snack after
Some follow up questions I get are …
- How much am I supposed to eat? Generally, most bodies can tolerate 1g/kg of carbohydrate in the hour before physical activity. The carbohydrate source should be low in fiber, fat, and protein to avoid GI distress.
- So you’re telling me to eat a lot of sugar and starch before a workout? Yes and no. Ideally, the preworkout snack isn’t the “make or break” instance of eating. The meals and snacks prior should provide the bulk of the fuel, and the preworkout snack is to “top off the tank. Ideally, we’re not always relying on sugar, but we’re giving ourselves enough time to have more whole grain choices. But if sugar is where we’re at, due to timing and availability, do it!
- Why not protein / fat in the hour before a workout? Your stomach needs blood to digest foods – particularly proteins and fat. However when you’re training, your muscles ALSO need more blood for fuel and cooling. This creates a challenge for the body – who gets the blood? As a result, people end up either feeling fatigued OR with a stomach ache, particularly if they’re trying to workout at very high intensities OR in hot conditions. Examples of challenging foods may be – eggs, yogurt, milk, cheese, bacon, sausage, meats in general, cottage cheese. However, if you’re working out at lower intensities (or have a stomach of steel), it’s not as big of a consideration
- But won’t fiber prevent me from “crashing?” Isn’t it “healthy?” I’m not saying that anything is good or bad for you. Fiber has a lot of benefits, but eating it takes up a lot of room in the stomach and for some, can cause GI upset for some people (particularly those working at high intensity). Additionally, foods with loads of fiber often aren’t as energy dense so you have to eat a larger portion in order to get the fuel you need. So while a bowl of berries sounds like the “healthier” option, it would take almost 1 1/2 cups of berries to get the same energy from a slice of bread.
- What about caffeine? While caffeine is an ergogenic aid (aka, it reduces the perceived effort of workouts so you perform better – particularly for endurance activity), it has a bell curve. That means caffeine has been shown to improve performance in small doses, but quickly reduces performance if taken in excess. Additionally, too much caffeine easily cause diarrhea, increase you heart rate, make you jittery, dehydrate, and leave you exhausted. It can also interrupt your sleep quality if you’re consuming it later in the day, which impairs recover. So a cup of coffee can be helpful before morning workouts, but more may reduce your performance.