Is quitting sugar good for athletes? The nuanced answer for peak performance

October 16, 2025 •

4 min read

According to one study, athletes who followed a moderate-sugar, high-carbohydrate diet performed better over 12 months than those with excessive intake, suggesting that context is everything. The answer to "is quitting sugar good for athletes?" is highly dependent on an athlete's specific needs, training intensity, and the type of sugar being consumed.

Quick Summary

Quitting refined, added sugars offers health benefits, but for athletes, simple carbs are essential for fueling intense activity and replenishing glycogen stores for recovery.

Key Points

Not all sugar is bad: For athletes, the timing and type of sugar are critical. Added, refined sugars are harmful, but simple carbs are necessary for performance.
Glycogen is vital: Your body stores carbohydrates as glycogen, the primary fuel for high-intensity exercise. Quitting sugar can deplete these stores, leading to fatigue.
Strategic timing is key: Consume fast-digesting simple sugars before and during intense workouts, and again with protein for recovery, to maximize performance and replenishment.
High sugar intake has consequences: Excessive, non-timed sugar consumption can lead to energy crashes, inflammation, and impaired recovery, even in athletes.
Moderation over elimination: The healthiest approach for an athlete is to minimize added sugars outside of training and rely on nutrient-dense whole foods, rather than a complete ban.
Listen to your body: The optimal amount of sugar and timing can vary by individual, sport, and exercise intensity. Personalized strategy is more effective than a one-size-fits-all approach.

The athlete's dilemma: All sugar is not created equal

For many in the general population, reducing or eliminating added sugar is a clear path to better health. However, for an athlete, the relationship with sugar is far more complex. The body requires carbohydrates—which break down into simple sugars like glucose—as its primary, fast-acting energy source for high-intensity and prolonged exercise. Completely quitting all sugar, including strategically timed simple carbs, can significantly impair performance, endurance, and recovery. The key distinction lies between the empty calories of refined, added sugars and the essential fuel provided by carbohydrates in a balanced, timed manner.

The crucial role of glycogen for performance

Glycogen is the stored form of glucose in the muscles and liver, and it is the most important energy substrate for athletes, especially during higher-intensity exercise. Muscle glycogen is the readily available fuel source that powers muscle contractions. Its availability directly impacts an athlete's capacity and time to exhaustion. For example, studies have shown that high muscle glycogen content allows endurance athletes to perform longer and faster. This is why post-workout refueling with carbohydrates is critical for recovery and preparing for the next session. Insufficient carbohydrate intake leads to low glycogen stores, resulting in fatigue, decreased endurance, and impaired recovery. This can even force the body into a catabolic state, where it breaks down muscle tissue for energy.

The downside of excessive added sugar

While strategic carbohydrate intake is vital, a diet high in excess added sugar comes with significant drawbacks for athletes. Over-consuming sugary foods and drinks outside of training can cause energy spikes followed by crashes, leading to sluggishness and impaired focus. Excessive added sugar intake has also been linked to negative long-term health outcomes, even in physically active individuals, including inflammation, insulin resistance, and increased fat storage. These issues can hinder an athlete's progress and overall health.

Here are some of the negative effects of a diet high in added sugar:

Energy Crashes: Rapid spikes in blood sugar followed by steep crashes leave athletes feeling fatigued and unfocused, negatively impacting training and competition.
Increased Inflammation: Chronic, high sugar intake can increase inflammation in the body, potentially delaying muscle recovery and increasing the risk of injury.
Gastrointestinal Distress: High consumption of simple sugars during exercise can cause bloating, cramping, and nausea, especially during intense efforts.
Metabolic Inflexibility: Over-relying on sugar for fuel can hinder the body's ability to efficiently burn fat for energy, which is important for long-duration events.

The strategic timing of carbohydrates

For athletes, the conversation should shift from 'quitting sugar' to 'strategically timing high-glycemic carbohydrates.' A sports nutritionist will emphasize the difference between nutrient-dense, complex carbs for general health and daily fueling versus simple sugars timed around exercise to maximize performance. This strategic approach leverages sugar for its quick energy benefits without exposing the body to the long-term detriments of chronic, high sugar consumption.

Comparison of fueling strategies

To illustrate the difference, consider the following comparison:


Feature	Excessive Added Sugar Approach	Strategic Sugar Timing Approach
Carb Source	Primarily from processed foods, sugary drinks, and snacks throughout the day.	Primarily from complex carbohydrates (whole grains, fruits, vegetables) and simple sugars strategically timed for workouts.
Energy Levels	Volatile, with frequent energy spikes and crashes that lead to fatigue and poor concentration.	Stable and consistent, with sustained energy from whole foods and targeted boosts during exercise.
Glycogen Stores	Potentially inadequate replenishment due to poor overall nutrition and untimely intake.	Optimized replenishment by consuming high-glycemic carbs within the recovery window.
Training Impact	Subpar performance, decreased endurance, and impaired recovery due to energy deficits and inflammation.	Enhanced performance, improved endurance, and faster recovery due to optimal glycogen availability.
Health Impact	Increased risk of inflammation, insulin resistance, weight gain, and related health issues.	Reduced inflammation and improved metabolic health by minimizing added sugars outside of key fueling periods.

Fueling windows for optimal performance

Instead of banning all sugars, athletes should focus on strategic intake around training sessions and competitions.

Before Exercise: Simple carbohydrates consumed roughly 1-4 hours before intense or long-duration activity can top up glycogen stores and provide quick, accessible energy. Examples include a banana, a sports drink, or a small handful of fruit snacks.
During Exercise: For activities lasting longer than an hour, consuming 30-60 grams of simple carbohydrates per hour can prevent glycogen depletion and delay fatigue. For ultra-endurance events, this can increase to 90+ grams per hour using multi-transportable carbohydrate sources.
After Exercise: Within an hour of finishing a strenuous workout, consuming a combination of high-glycemic carbohydrates and protein is crucial for rapid glycogen replenishment and muscle repair. Chocolate milk is a classic example that combines both.

Conclusion: Finding the sweet spot for athletic success

For athletes, quitting sugar entirely is not recommended and can negatively impact performance. The key is to differentiate between the empty calories of added sugars found in processed foods and the essential, timely intake of simple carbohydrates that fuel intense exercise and aid recovery. By focusing on nutrient-dense complex carbs for daily energy and strategically using simple sugars before, during, and after workouts, athletes can maintain peak performance, stabilize energy levels, and reduce the health risks associated with excessive sugar consumption. The goal is not elimination, but smart, strategic integration into a balanced dietary plan that supports both short-term performance and long-term metabolic health.

Frequently Asked Questions

Reducing added sugar intake often leads to weight loss because it decreases overall calorie consumption, but athletes need to ensure adequate energy from other carbohydrates to prevent performance drops.

While fruits and complex carbs are excellent for daily energy and health, simple sugars from other sources are often needed to provide the rapid fuel required for high-intensity exercise and quick recovery.

An endurance athlete who completely quits sugar will likely face premature fatigue and decreased performance, as their glycogen stores will not be adequately replenished for prolonged, intense activity.

Yes, excessive and chronic intake of added sugars has been linked to increased inflammation, which can hinder muscle recovery and overall health.

The best times are typically before exercise (1-4 hours) to top up fuel, during exercise (for activities over 60 minutes) to sustain energy, and immediately after to kickstart recovery.

Reducing added sugars can improve metabolic health, including better insulin sensitivity and reduced inflammation. However, for athletes, strategic carbohydrate intake is still necessary to avoid performance issues.

Avoid relying solely on large amounts of simple sugars at once. Instead, consume smaller, regular amounts during prolonged exercise, or use slower-release carbohydrates, to maintain more stable blood glucose levels.