Athletes need significantly more sugar than the general population, but the right amount depends on training duration, intensity, and timing. While the World Health Organization recommends non-athletes limit free sugars to less than 10% of daily calories, athletes burning through glycogen stores during hard training sessions operate under a completely different set of rules. For a 70 kg (154 lb) endurance athlete training two or more hours a day, sugar intake during and after exercise alone can exceed 150 grams, well beyond what would be considered healthy for a sedentary person.
Why Athletes Need More Sugar
Sugar is a fast-burning fuel. Your muscles store carbohydrates as glycogen, and during moderate to intense exercise, glycogen is the primary energy source. When those stores run low, performance drops sharply. Simple sugars, the kind found in sports drinks, gels, and fruit, are absorbed quickly and can keep you fueled when complex carbohydrates would sit in your stomach.
The general health advice to minimize sugar exists because sedentary people don’t burn through glycogen the way athletes do. Excess sugar in a low-activity body contributes to metabolic problems. But during prolonged exercise, your muscles are pulling glucose out of the bloodstream so fast that the metabolic concerns largely don’t apply. Context changes everything.
During Exercise: 30 to 90 Grams Per Hour
The American College of Sports Medicine recommends 30 to 60 grams of carbohydrate per hour during endurance exercise lasting longer than one hour, or roughly 0.7 grams per kilogram of body weight per hour. For most athletes, this means consuming simple sugars in the form of sports drinks, gels, chews, or diluted juice.
Your body can oxidize a single sugar source (like glucose alone) at a maximum rate of about 60 grams per hour. That’s a hard ceiling set by intestinal absorption. But combining two types of sugar pushes that limit higher, because glucose and fructose use different transport pathways in the gut. When you mix them, absorption rates climb to around 90 grams per hour, sometimes slightly higher. The sweet spot for this combination appears to be roughly a 1:0.8 glucose-to-fructose ratio, which delivers the most usable energy while minimizing stomach issues.
The performance payoff scales with duration. For workouts under an hour, you likely don’t need any sugar at all. Between one and two hours, 30 grams per hour is a reasonable starting point. Sessions lasting two to three hours benefit from 60 grams per hour. Ultra-endurance events pushing past three hours call for up to 90 grams per hour, ideally from a glucose-fructose blend. The greatest performance improvements in research have been observed at ingestion rates between 60 and 80 grams per hour during efforts lasting 2.5 hours or longer.
After Exercise: Restocking Glycogen Fast
Recovery is where sugar intake can climb even higher, especially if you need to perform again within 24 hours. Research on well-trained cyclists found that consuming 1.2 grams of carbohydrate per kilogram of body weight per hour for the first six hours after exercise rapidly replenished liver glycogen. For a 70 kg athlete, that’s 84 grams per hour, or roughly 500 grams of carbohydrate in those six hours alone.
That level of intake is aggressive and primarily relevant for athletes with two-a-day training sessions or multi-stage competitions. If your next workout is 24 or more hours away, you have more flexibility. Eating carbohydrate-rich meals at a normal pace will restore glycogen adequately without the urgency. One important finding from that research: even with very high carbohydrate intake (10 grams per kilogram of body weight over 12 hours), liver glycogen bounced back quickly but muscle glycogen took longer. Full muscle recovery simply takes time regardless of how much you eat.
Daily Totals by Sport Type
Putting this together into a full day depends on your training load. General sport nutrition guidelines break down roughly as follows:
- Light training (under 1 hour): 3 to 5 grams of total carbohydrate per kilogram of body weight per day. Most of this can come from whole grains, fruit, and starchy vegetables. Added sugar needs are minimal.
- Moderate training (1 to 2 hours): 5 to 7 g/kg/day. Some simple sugar around workouts helps, but the bulk still comes from whole food sources.
- High-volume endurance training (2 to 4 hours): 7 to 10 g/kg/day. A significant portion of this, potentially 100 to 200 grams, may come from simple sugars consumed during and immediately after training.
- Extreme endurance (4+ hours): 10 to 12 g/kg/day. At this level, it becomes physically difficult to eat enough without relying on easily digested sugars.
For a 70 kg athlete doing high-volume training, that’s 490 to 700 grams of total carbohydrate per day. Of that, simple sugars might account for 150 to 300 grams, consumed mostly during and after exercise. For a strength or power athlete training an hour a day, simple sugar needs are far lower, perhaps 30 to 50 grams around workouts, with the rest of their carbohydrates coming from whole foods.
Timing Matters More Than Total Grams
When you eat sugar changes how your body handles it. High-glycemic sugars (the fast-absorbing kind) cause a rapid spike in blood glucose. Before exercise, this can actually backfire. Research shows that a high-glycemic meal eaten shortly before training causes blood sugar to drop sharply within the first 10 to 20 minutes of exercise, even though it initially raises blood sugar higher than a slower-digesting meal. A lower-glycemic meal eaten two to three hours before exercise tends to produce more stable blood sugar during the session.
During exercise, the equation flips. Fast-absorbing sugars are ideal because your muscles are actively pulling glucose from the blood. This is when gels, sports drinks, and other high-glycemic options earn their place. After exercise, fast sugars combined with a full meal accelerate glycogen restoration.
The practical pattern for most athletes: slower-digesting carbohydrates in meals eaten well before training, simple sugars during sessions longer than an hour, and a mix of both in post-workout meals.
How to Choose Your Sugar Sources
Not all sugars perform equally during exercise. Products combining glucose (or maltodextrin, which breaks down into glucose) with fructose consistently outperform single-sugar options. This is why many sports nutrition products list both maltodextrin and fructose on the label, typically in a roughly 2:1 or 1:0.8 ratio. This combination allows higher absorption rates and tends to cause less bloating and cramping than glucose alone at the same dose.
Common mid-workout options that fit this profile include commercial sports drinks, energy gels, gummy chews, and even flat cola mixed with a pinch of salt. Whole foods like bananas, dates, and rice cakes work well for longer, lower-intensity efforts where digestion isn’t as stressed. During very intense exercise, liquid or semi-liquid sources are easier on the stomach.
Outside of the training window, your sugar intake should look more like the general population’s. Whole fruits, dairy, and naturally occurring sugars in foods are fine. The sugars that health organizations flag as problematic, sweetened beverages, candy, and heavily processed snacks, don’t serve athletes any better than anyone else when consumed outside of exercise. The metabolic free pass for sugar really only applies when your muscles are actively demanding fuel or restocking it.