Fueling Fitness: What Your Body Actually Needs Before, During, and After Exercise
Fueling Fitness: What Your Body Actually Needs Before, During, and After Exercise
As the weather warms up, more people start thinking about getting outside and being more active. Whether that is walking, hiking, cycling, strength training, or something else entirely, it all counts.
Before getting into fueling, it helps to define what we mean by “exercise” because not everyone understands the difference between exercise and movement or physical activity.
What Counts as Exercise?
Exercise is a structured, intentional form of physical activity. Think strength training, running, or a planned workout.
Physical activity is broader. It includes anything that gets you moving. Walking the dog, gardening, cleaning, or taking the stairs all count.
Both matter – so it’s not to say that if you aren’t doing exercise, then you aren’t doing anything. However, we do want to include exercise as part of our activity.
The Physical Activity Guidelines for Americans recommend:
At least 150 minutes of moderate-intensity activity per week
Muscle-strengthening activities at least two days per week
That does not have to happen all at once. It can be built gradually. Starting small and building consistency is often more effective than going all in and burning out.
Keep in mind that the 150 minutes a week can be five bouts of 30 minutes, four bouts of 40minutes, three bouts of 50 minutes, you get the idea. Similarly, the muscle-strengthening activities target the major muscle groups: arms twice a week and legs twice a week, etc.
I tend to do upper body one day, lower body the next day, and then a full-body workout a third day – after sufficient rest from the prior two exercise days. So, day one and day two are the upper and lower, then rest on day three, then a full-body workout on day four. This is just an example, not what you need to do.
Fueling Fitness Is Not One-Size-Fits-All
There is no single “right” way to fuel exercise. Having taught sports nutrition for years now, I find the most common questions are when exactly…, how much exactly…, and what exactly…. Unfortunately, this isn’t how nutrition works, let alone how it fuels fitness and sports nutrition.
What “works” depends on many factors, including:
Type of activity
Duration and intensity (how long and how hard)
Personal preferences
Digestive tolerance
Time since last meal
Time of day
Training status
That is why two people can follow completely different routines, and both feel great. Or one person has different fueling strategies for a group fitness class or a strength-training session than for a morning run or a weekend bike ride.
That said, there are three key nutrition components that consistently matter.
1. Hydration: The Most Overlooked Factor
Hydration is often underestimated, but it is one of the most important parts of performance and recovery. Heck, it is one of the most important parts of life.
Even mild dehydration can lead to:
Fatigue
Headaches
Reduced performance
Increased perceived effort
What to Drink – It’s Not Complicated
Water works well for most activities.
Electrolytes may be helpful when:
Exercise lasts longer than 60 to 90 minutes
You are sweating heavily – and even more so if you are a salty sweater.
You are in hot environments regardless of humidity
How Much?
There is no universal number, but general guidance:
Before: drink fluids throughout the day and have 8 – 16 fluid ounces 1 to 2 hours before activity
During: sip as needed, especially for longer sessions (general guidance is 4 – 8 fluid ounces every 15 – 30 minutes)
After: replace what was lost through sweat; that’s 16 fluid ounces for every pound lost
A realistic, practical way to check hydration is urine color. Pale yellow is a good sign. Dark, amber, apple juice? Not good.
2. Carbohydrates: Your Primary Fuel
What Should I Eat Before a Workout?
You need to find what works best for you. Here are some suggestions to get started:
Banana
Toast with peanut butter
Yogurt with fruit
Oatmeal
Crackers and cheese
Apple with peanut butter
Carbohydrates tend to get a bad reputation, but when it comes to exercise, they are essential.
They are the body’s preferred energy source, especially for moderate to high-intensity activity.
What Happens Without Enough Carbs?
Low energy
Early fatigue
Reduced performance
That “dragging through the workout” feeling
When to Include Carbs
Before exercise
Helps top off energy stores
Examples: toast, fruit, oatmeal, yogurt with fruit
During exercise
Typically, carbs are needed during exercise only for longer or more intense sessions, like more than 75 minutes
Examples: sports drinks, fruit, energy chews
After exercise
Helps replenish energy stores
Best paired with protein
How Much?
It depends on the activity, but the key is to experiment and find what feels best.
Carb loading is not necessary for most people. That strategy is typically reserved for endurance events lasting several hours. This has a specific strategy over several days and not just the night before.
3. Protein: Recovery and Repair
Protein is important, but not for fueling the workout itself. This is often misunderstood.
Its primary role is:
Muscle repair
Recovery
Adaptation to training
What Happens Without Enough Protein?
Slower recovery
Increased soreness
Reduced ability to build or maintain muscle
Timing Protein
After exercise
Helps support recovery
Can be part of a meal or snack
Throughout the day
Spreading protein intake is more effective than consuming it all at once
What If You Focus Only on Protein?
If protein replaces carbohydrates, energy levels may suffer. Both are needed, just for different reasons.
So, focus less on the protein before and during, and prioritize it for after the workout.
Nutrient Timing: Helpful, Not Precise
Nutrient timing can support performance and recovery, but it does not have to be exact.
For recreational activity:
Eating something before exercise can help
Refueling can support recovery
Missing a “perfect window” is not a problem
Consistency matters more than precision.
What Happens When You Are Under Fueled?
This is more likely to occur, based on my experience, because there is the idea that we need to eat in a “fasted” state. When the body is not adequately fueled, you may notice:
Low energy
Poor performance
Increased injury risk
Difficulty recovering
Loss of motivation
This is especially common when people restrict carbohydrates or under-eat overall. If exercise is a struggle, not that you don’t want to do it, but it is really just a chore to get through, physically hard to do, you could be under-fueled.
Common Sports Nutrition Myths
Along with that, “exercising fasted,” there are plenty of sports nutrition myths. Let’s clear up a few common ones.
“Fasted exercise burns more fat.”
Not in a meaningful way for long-term outcomes. It often just leads to lower performance. Fueling for a workout can lead to a better, more efficient workout and actually burn more calories overall, which means more fat is burned later too.
“Low and slow burns more fat.”
Different intensities use different fuel sources, but overall energy balance matters more. Again, if you do a higher intensity workout, there is more “afterburn” or carry over of calories burned after the activity is done – meaning it is more likely to tap into fat stores.
“Cutting carbs improves performance or weight loss.”
Carbs are essential for fueling activity. Removing them can make exercise feel harder. And, when people cut out carbs, water follows. So, that “weight loss” is often water weight.
“You can out-exercise a poor diet.”
Exercise supports health, but nutrition plays a larger role in overall outcomes. What this means is exercise does burn calories, but the quality of the diet and the overall quantity are still important. This is one of the biggest “aha” moments for people.
“Sports drinks are always necessary.”
Not for most workouts. Water is usually enough. Unless you lose a lot of fluids and sodium or need to replenish glucose, plain water is just fine.
“Exercise prevents heart disease completely.”
Exercise helps, but it is one piece of overall health. People are often surprised to learn or hear of someone who had a heart attack or similar episode, even though they are avid exercisers. It happens, but it is not an excuse to not exercise. Just know that there are many measures of health, and exercise can help improve many aspects of it. But it is not a guarantee.
Practical Fueling Ideas
This is where many people just want some simple, realistic examples of what to do. So here are some examples, but remember these are guidelines, suggestions, recommendations, but not rules. You must be your own detective and find what works best for you.
Morning Exercise
Before
Banana
Toast with peanut butter
After
Smoothie with milk, fruit, and protein
Eggs with toast
Midday Exercise (like a lunch time workout)
Before
Yogurt with fruit
Oatmeal
After
Balanced lunch with carbs, protein, and vegetables
Afternoon or After-Work Exercise
Before
Crackers and cheese
Apple with peanut butter
After
Dinner that includes grains, protein, and vegetables
Longer or More Intense Workouts
Longer means generally more than 75 – 90 minutes; more intense is less than that, but it is non-stop at a higher intensity.
During
Sports drink
Fruit
Energy chews
What To Remember
Fueling fitness does not have to be complicated.
Hydration matters more than most people realize
Carbohydrates are essential for energy
Protein supports recovery
Timing can help, but it does not need to be exact
A balanced approach works better than extremes
There is no single “right” way to do this. The goal is to find what works for your body, your routine, and your preferences.
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