When 'Healthy' Eating Actually Hurts Your Performance
That green smoothie and quinoa bowl might be healthy — but it might also be sabotaging your training. Learn why some healthy foods hurt athletic performance.
Quick Answer
High-fiber, high-fat, and "healthy" whole foods can hurt performance by causing GI distress, slowing digestion, and crowding out carbs. Time these foods around training, not before.
You're doing everything right. Green smoothies, whole grains, chia seeds, and cruciferous vegetables.
But your training feels off. You're bloated during hard efforts. Your race times aren't improving.
The problem might be that your "healthy" foods aren't helping your performance.
The Problem with Healthy Foods
There's a difference between foods that are healthy for the general population and foods that help athletes perform.
Many healthy foods are high in fiber, fat, or compounds that slow digestion — perfect for everyday health, terrible for performance timing.
Foods That Hurt Performance
- High-fiber cereals and breads (slow carb absorption)
- Cruciferous vegetables (broccoli, cauliflower, kale — gas and bloating)
- Beans and legumes (high fiber, known GI distress)
- Chia seeds and flaxseed (expand in gut, slow digestion)
- High-fat nuts and avocados (slow gastric emptying)
- Large amounts of fruit juice or smoothies (fructose overload)
Why These Foods Cause Problems
- Fiber absorbs water and slows gastric emptying
- Fat takes longer to digest than carbs
- Certain FODMAPs in healthy foods cause fermentation and gas
- Some compounds interfere with carb absorption
The Performance Nutrition Rule
Timing is everything:
- Before exercise: simple, low-fiber, low-fat carbs
- During exercise: fast-absorbing gels, drinks, chews
- After exercise: carbs + protein for recovery
- Between workouts: add fiber, fat, and micronutrients
What to Eat Before Training
- White bread, bagels, or rice cakes
- Bananas, applesauce, or melon
- Honey or jam on simple carbs
- Small amount of protein (optional)
- Avoid: whole grains, seeds, nuts, raw vegetables
The Rest of the Day
Here's the key insight: you can eat those healthy foods — just not immediately before or during exercise.
- Post-workout: Add back fiber and healthy fats
- Between workouts: Enjoy your green smoothies and whole grains
- Evening meals: Load up on micronutrient-dense foods
- The goal: performance during training, nutrition all day
The Balance
You don't have to choose between health and performance. You need to time them correctly:
- Performance window: Prioritize carbs, fast digestion
- Non-training time: Prioritize fiber, micronutrients, variety
- Your body needs both for long-term health and results
Time your nutrition for performance.
Download MAVRFrequently Asked Questions (FAQ)
Can I never eat fiber before exercise?
Small amounts of lower-fiber fruits and vegetables are fine. Just avoid large servings of high-fiber foods within 2–3 hours of training.
What about oatmeal before a marathon?
Oatmeal can work for some athletes, but many prefer lower-fiber options. Test extensively in training before race day.
Does this apply to cycling too?
Yes. Cycling has similar GI concerns, though athletes may tolerate slightly more solid food on the bike.
How does MAVR help with food timing?
MAVR provides specific food recommendations for each time window around your training.