Sugar Intake for Athletes: Enemy or Fuel? A Coach's Guide to Understanding Sugar in Daily Life and Sports

Opening: A Student Who Feared Sugar Too Much

A few years ago, I coached a student in his early forties, an office worker—let’s call him A-Zhe. He was very diligent. The moment his health check report flagged “elevated blood sugar,” he cleared out every sugary item in his house, and even refused energy gels and sports drinks during exercise. That year, he took on the long-distance Yangjin P-Road climb. Halfway through, near Fengguizui, he completely “bonked”—legs gave out, hands shook, cold sweat, and his mind started to drift. He only slowly recovered after a teammate shoved an energy gel into his hands. Afterwards, he asked me, puzzled: “Coach, isn’t sugar a bad thing? I’ve cut it out so thoroughly in daily life—why did this happen during exercise?”

This question is actually the one I’ve been asked the most—and the one most easily misunderstood—in my fifteen years coaching athletes at all levels and recreational exercisers. Is sugar an enemy, or fuel?

My answer: It’s both, but it depends on the context. Conflating “cutting sugar in daily life” with “supplementing sugar during exercise” is the first trap many sports enthusiasts fall into. In this article, I want to break this down clearly, in the same tone I use with my students—when sugar is the fuel that helps you finish the race, when it might quietly erode your health, and most importantly: how to strike the balance between the two.

Here’s the takeaway for those in a hurry: In daily diet, “added sugar” should be limited; but during moderate-to-high-intensity exercise lasting over an hour, moderate sugar supplementation isn’t a sin—it’s key to protecting performance and brain function. These two things don’t contradict each other.

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Concepts and Scientific Foundations: What Role Does Sugar Actually Play in the Body

1. Sugar Is the Body’s Most “Ready-to-Use” Energy Currency

The carbohydrates we eat are mostly broken down into glucose, which enters the bloodstream as “blood sugar,” or is stored as “glycogen” in the liver and muscles. Think of it as two types of wallets:

• Blood sugar: Like loose change in your pocket—ready to use anytime, but limited in amount and fluctuates quickly.
• Muscle and liver glycogen: Like cash stashed in a drawer—more substantial, but not unlimited either.

The average adult’s total glycogen storage is roughly in the 300 to 600 grams range (varying by body type, training level, and diet), which translates to about 1200 to 2400 kcal. That sounds like a lot, but if you actually tackle a long climb like the west approach of Wuling, or run a full marathon, energy expenditure at moderate-to-high intensity easily hits 600 to 900 kcal per hour. That’s when you realize—no matter how much you have in savings, you can’t spend it that fast.

This is exactly why A-Zhe “bonked” back then. What sports medicine calls “hitting the wall” or “bonking” is essentially glycogen being depleted, blood sugar failing to hold up, and the body and brain entering an energy crisis simultaneously. And don’t forget, the brain relies almost entirely on glucose to function—that’s why when blood sugar drops, it’s not just your legs that lose power; your judgment, focus, and mood all collapse too. On a long ride, if blood sugar gets too low on a steep descent or in heavy traffic, slowed reaction time is a real safety risk—not just a matter of “underperforming.”

I often use a simple analogy with my students: Glycogen is like a phone battery. Used normally, it lasts all day; but if you keep the brightness maxed out and run heavy games (i.e., high-intensity exercise), the charge drains fast. Supplementing sugar during exercise is like “charging while playing”—you can’t fill the battery instantly, but you can slow the drain and make it last longer, avoiding a mid-ride shutdown.

2. Why Can’t Fat Fully Take Over During Exercise?

Some people ask: “Don’t I have plenty of fat to burn? Why do I still need sugar?”

Here’s the key concept: Fat reserves are vast, but the “burn rate” has a ceiling. The higher the intensity, the more the body relies on sugar for energy, because sugar produces energy faster. When you’re riding near your lactate threshold, or holding marathon pace, fat can’t supply energy fast enough—that’s when sugar becomes the irreplaceable high-octane fuel. Well-trained endurance athletes can improve their “fat utilization capacity,” but no one can finish a high-intensity long-distance effort on fat alone.

3. Daily “Sugar” and Exercise “Sugar” Are Fundamentally Different Things

This is the most important section of the entire article—please remember it. When health headlines say “sugar is the culprit behind chronic disease,” they’re usually talking about “free sugar/added sugar”—the kind added to bubble tea, sugary drinks, pastries, and processed foods. The World Health Organization (WHO) recommends that adults and children keep daily “free sugars” intake below 10% of total calories, and further reducing it to below 5% (roughly 25 grams per day, about 6 teaspoons) offers additional health benefits (sources listed in the references at the end).

But sugar supplemented during exercise to maintain performance belongs to a completely different usage context:

• It’s taken in while your glycogen is being heavily depleted;
• It gets burned immediately, not stored as fat;
• Its purpose isn’t “enjoying sweetness,” but “maintaining function.”

In other words, the same sugar—downed with a pearl milk tea at the office versus swallowed while climbing at a heart rate of 165 bpm—means vastly different things to the body. Equating exercise supplementation with daily sugar reduction is a conceptual mix-up.

4. Fast Sugars vs. Slow Sugars: Differences in Glycemic Response

Let me add one more practical concept. Carbohydrates can be roughly divided by “speed of entering the bloodstream” into faster-acting ones (like glucose, white rice, white bread, sugary drinks) and slower-acting ones (like oats, brown rice, sweet potatoes, legumes, due to fiber and more complex structures). This applies in daily life and during exercise in exactly opposite ways:

• Daily life, for stable blood sugar and avoiding spikes and crashes: Lean toward slower-acting, fiber-rich whole-food carbs, so blood sugar doesn’t ride a roller coaster.
• During exercise, for quick energy: You actually want fast-acting, easily absorbed sugars, because what you need is “immediately burnable.”

That’s why energy gels and sports drinks are designed as “fast sugars”—they’re meant to deliver support the moment you need it. But the same sugary drink, sipped slowly at your desk, spikes blood sugar with nowhere for it to go—and long-term, that’s a burden. See, the key is always ‘which context it’s used in.’

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Practical Method 1: How Much Sugar Should You Actually Take During Exercise?

This is what students want to know most. Let’s start with the general principle, then give a dosing table.

In sports science, there’s a widely cited principle for “hourly carbohydrate intake during exercise”: The longer and more intense the exercise, the more carbs you need. Based on current nutrition guidelines and research (sources at the end), the general direction is:

• Under 1 hour of exercise: Usually little to no extra sugar needed; water or a carbohydrate mouth rinse is sufficient.
• 1 to 2 hours of moderate-to-high-intensity exercise: Roughly 30 to 60 grams of carbs per hour.
• Over 2 to 2.5 hours of prolonged exercise: Consider increasing to 60 to 90 grams per hour, but this typically requires “gut training” to tolerate and absorb.
• Some elite athletes, after thoroughly training their gut, attempt higher intakes (some studies mention a range of 90 to 120 grams/hour), but this isn’t something recreational enthusiasts should copy directly.

Hourly Carbohydrate Intake Reference Table

Exercise Duration	Recommended Carbs per Hour	Suitable For	Practical Examples
< 60 minutes	Barely necessary	Everyone	Plain water is fine; for high intensity, swish a mouthful of sports drink and spit it out
60–90 minutes	30–45 g	General fitness enthusiasts	1 energy gel + a few sips of sports drink
90–150 minutes	45–60 g	Advanced athletes with a foundation	Sports drink + alternating energy gel/banana
2.5+ hours	60–90 g	Requires prior gut training	Glucose + fructose mixed fueling, taken in small, frequent portions

Coach’s Note: The table provides a “range,” not a “decree.” Everyone’s gut tolerance, sweat rate, and the day’s temperature are different. Treat it as a starting point, test and fine-tune it during training days, and find the amount you can handle without bloating.

Why Mix “Glucose + Fructose”?

This is a very practical detail. The human gut has a limit on the “pathway” for absorbing glucose. Relying on glucose alone, absorption tops out at around 60 g per hour before it gets backed up. But fructose uses a different absorption pathway, so by mixing glucose and fructose in a certain ratio (commonly discussed around 2:1), you can push total absorption higher. That’s why, when ultra-long distances require intake above 60 g, people emphasize using a “glucose + fructose” blend rather than a single sugar.

What Is “Gut Training”?

Many people stuff themselves with gels at their first race, only to suffer from diarrhea and nausea in the second half—this isn’t a fitness issue, it’s an untrained gut. The gut’s ability to absorb sugar can actually be trained. The method is simple: during your regular long-distance training, follow the same fueling rhythm you’ll use in the race, letting your gut get used to processing those sugars while exercising. This is just as important as training your legs and cardio, yet it’s the most commonly overlooked aspect.

I usually ask athletes to formally add “fueling” to their training plan starting 6 to 8 weeks before the race. The approach: treat every long-distance session over 90 minutes as a dress rehearsal—drink the sports drink, eat the energy gels, and stick to the timing schedule exactly as planned, while logging everything. Which gel makes you nauseous, which rhythm causes bloating, how hot it has to be before you feel like throwing up—these can only be discovered through training, never left to luck on race day.

Comparison of Common Fueling Products

Many athletes stand in the store unsure what to pick. Here’s a table for your reference:

Fueling Product	Advantages	Disadvantages / Cautions	Best Timing
Energy Gel	High concentration, easy to carry, fast absorption	Must be taken with water, otherwise prone to nausea and bloating	Main fueling for moderate-to-high intensity, long distances
Sports Drink	Replenishes carbs, water, and electrolytes simultaneously	If too concentrated, absorption suffers; amount needs controlling	Long durations, heavy sweating
Banana	Natural, easy to digest, contains potassium	Inconvenient to carry, imprecise to quantify	Low-to-moderate intensity, relaxed long rides
Energy Bar / Rice Ball	Provides satiety, real food	Slower to digest, unsuitable for high intensity	Low-intensity segments of ultra-long distances
Dried Fruit / Gummies	Convenient, gives a psychological “reward” feeling	Pure added sugar, lacks electrolytes	Quick bite for short durations

Coach’s Note: There’s no “best fueling product,” only “the one best suited to your current situation.” In the same long-distance event, starting with real food and switching to easily absorbed energy gels later is a very common combination.

How to Do “Carb Loading” Before a Race?

If you’re taking on a grueling event lasting over 2.5 hours—like the Wuling west ascent, Taroko long-distance, or a full marathon—topping off the “fuel tank” beforehand is crucial. This is called carb loading. The concept isn’t hard: in the 1 to 3 days before the race, moderately increase your carbohydrate ratio while reducing training volume (tapering), giving your body the chance to store glycogen to the max.

Timing	Approach	Plain-Language Key Point
3–4 days before	Start tapering training, keep carbs at normal-to-high levels	Give your body room to store
1–2 days before	Increase carb ratio, choose easily digestible sources (white rice, noodles, sweet potatoes)	Fill the tank; avoid high-fat, high-fiber, hard-to-digest foods
Pre-race meal	3–4 hours before, eat easily digestible carbs, don’t overeat	Provide fuel without burdening the gut
30–60 min before start	Optionally take a small portion of easily absorbed carbs	Works for some, causes discomfort in others—test it in training first

Note: Carb loading is not “binge-eating before the race.” That will only cause gut discomfort and weight gain without any benefit. The key is adjusting the ratio and choosing easily digestible foods, and it should also be rehearsed in training races or simulations.

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Practical Method 2: How to Balance Sugar in Daily Diet?

Feeling free to fuel with sugar during exercise doesn’t mean you can eat recklessly on a daily basis. Here’s a practical set of principles suited to life in Taiwan.

Three Realities of the Taiwan Context

1. Bubble tea culture: On Taiwan’s streets, a cup is never far away. A full-sugar, large bubble tea can easily approach or even exceed the WHO’s recommended daily limit for added sugar. This is the “hidden sugar” culprit I most often warn athletes to watch.
2. High proportion of eating out: Many sauces, thick soups, braised dishes, and breads hide sugar. You might think you haven’t eaten anything sweet, but it accumulates significantly over the day.
3. Hot, humid climate: Taiwan’s summers are muggy, and with heavy sweating during exercise, many people instinctively chug large amounts of sugary sports drinks to quench thirst—but if it’s just daily activity, not high-intensity exercise, most of that sugar goes unused and becomes excess calories.

Practical Tips for Reducing Daily Sugar

• Cut the “liquid sugar” first—it’s the easiest target: The sugar in sugary drinks and bubble tea is the most “imperceptible” and easiest to exceed limits. Switching from full sugar to half sugar, or from half sugar to light/no sugar, is the highest-value step.
• Save sugar for “useful moments”: Instead of drinking sweet things casually, reserve your carb allowance for before and after training, when you actually need the energy.
• Read labels, recognize keywords: “Sugar, sucrose, fructose, glucose syrup, high-fructose corn syrup, honey, concentrated fruit juice” in ingredient lists all count as added sugar.
• Prioritize whole foods: Sugar in fruit comes with fiber and vitamins, unlike the pure added sugar in bubble tea, so there’s generally no need for excessive worry—but fruit juice (especially from concentrate) deserves caution.

The “Hidden Sugar” List Taiwanese Often Overlook

I’ve had athletes keep food logs, and the most common finding is “I swear I didn’t eat anything sweet,” yet when it’s all laid out, it’s full of sugar. These everyday Taiwanese items are the hidden sugar sources I catch most often:

Hidden Sugar Source	Why It’s Easily Overlooked	Coach’s Advice
Full-sugar bubble tea	Drunk like water; one cup approaches the daily limit	Drop to light/no sugar, or switch to unsweetened tea
Breakfast shop milk tea, flavored milk	Thought of as a “side drink,” not counted	Switch to unsweetened soy milk or black coffee
Processed sauces (BBQ sauce, sweet and sour, ketchup)	Sugar in savory foods is the most imperceptible	Use less sauce, choose plain options
Bread, pineapple buns, sweet toast	Treated as a “meal” rather than dessert	Choose whole-grain, less-sweet options
Sports drinks as daily beverages	Assumed “sports” means healthier	Switch to water outside exercise
Energy drinks, sweetened coffee	Focused on the energy boost, ignoring sugar content	Read labels, choose sugar-free versions

Coach’s Note: You don’t need to become a sugar detective and stress yourself out. Focus on the big wins—handle the “liquid sugar” big boss first, and the results will already be obvious.

“Training Period” vs. “Non-Training Period” Must Be Viewed Separately

I often tell my students that your diet should be adjusted according to your training load. This is called carbohydrate periodization (the big picture):

Scenario	Carbohydrate Strategy	Plain Explanation
High-intensity training day / long-distance day	More carbohydrates	Give the body enough fuel; you can replenish before, during, and after training
Easy day / rest day	Cut back on carbohydrates	If you’re not burning that much, there’s no need to pile on the sugar
1–3 days before a race	Moderately increase carbohydrates (glycogen supercompensation concept)	Fill up the “fuel tank” to last through long distances
Daily non-exercise periods	Limit added sugars	Return to the WHO sugar-reduction principle

The spirit of this table is: Sugar is not something you “should always eat” or “should always avoid”—it should follow your activity level. This is also the real answer to the question “enemy or fuel”—it depends on the timing.

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Common Mistakes and Corrections

In all my years of coaching, I’ve seen the same mistakes countless times. Here are the most typical ones—see if any apply to you.

Mistake 1: “No sugar even during exercise,” like A-Zhe

Problem: Applying the daily sugar-reduction principle rigidly to long-distance exercise results in hitting the wall, running out of energy, and hypoglycemia. At best, performance collapses; at worst, dizziness and falls pose safety risks.

Correction: Distinguish between situations. For moderate-to-high-intensity exercise lasting over an hour, replenish as needed. The sugar burned immediately during exercise is not the “bad sugar” you need to guard against.

Mistake 2: Using a new supplement for the first time on race day

Problem: Without having trained your gut, suddenly cramming energy gels on race day causes stomach trouble—diarrhea, nausea, and bloating all hit at once.

Correction: “Never try anything new on race day” is an iron rule. All supplements, dosages, and timing must be tested during regular training. Your gut needs training too.

Mistake 3: Chugging sports drinks for short, easy exercise

Problem: Going for a leisurely 40-minute ride along the riverside while downing a large bottle of full-sugar sports drink means consuming a bunch of sugar you don’t need.

Correction: For exercise under an hour at non-high intensity, plain water is usually enough. Sports drinks are a tool for “when you need to replenish,” not a thirst-quencher.

Mistake 4: Focusing only on sugar, forgetting water and electrolytes

Problem: Taiwan’s summers are hot and humid, and you sweat a lot—and it’s salty. Replenishing sugar without water and sodium still leads to cramps and declining performance.

Correction: For long-duration exercise, you need to manage “sugar, water, and electrolytes” together. The value of sports drinks lies in providing all three, but you need to manage the concentration and amount.

Mistake 5: Treating “sugar-free” as a health cure-all while ignoring overall diet

Problem: Ordering all drinks sugar-free, but eating heavy, fatty meals, excessive refined carbs, and severely lacking vegetable fiber. You cut sugar, but overall diet quality is still poor.

Correction: Reducing added sugar is just one piece of the puzzle. A balanced diet centered on whole foods, with adequate fiber and protein, is the foundation.

Debunking Three Common Myths

Myth 1: “Carbs make you fat; athletes should avoid them as much as possible.”
Truth: What makes you fat is “long-term total calorie surplus,” not carbs themselves. For endurance athletes, carbs are the primary fuel; over-restricting them actually harms training quality and recovery.

Myth 2: “Sports drinks are always better than plain water.”
Truth: Sports drinks are designed for “prolonged, heavy sweating.” Drinking them for short, non-high-intensity exercise just means consuming unnecessary sugar and calories. Use the tool in the right situation.

Myth 3: “The more thoroughly you cut sugar, the healthier you are.”
Truth: Limiting “added sugars” in daily life is correct, but demonizing carbs, fruit, and normal staple foods as well can lead to insufficient energy during exercise, poorer recovery, and even affect mood and hormones. Moderation does not mean zero.

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On-the-Ground Practical Checklist

Here’s the whole article condensed into a checklist you can carry with you. Before heading out for training or a race, run through it quickly:

• [ ] How long and how intense is this session? (Determines whether and how much to replenish)
• [ ] Easy exercise under an hour → Just bring water, no extra sugar needed.
• [ ] Moderate-to-high intensity over an hour → Prepare energy gels / sports drinks / bananas according to the dosage table.
• [ ] Have you tested these supplements during training? (Never try anything new on race day)
• [ ] Hot weather, heavy sweating → Remember to manage sugar, water, and electrolytes together.
• [ ] Is your replenishment rhythm small amounts, frequent intervals, or do you plan to cram food in only when starving? (Choose the former)
• [ ] Have you cut back on bubble tea and sugary drinks this week?
• [ ] If you have blood sugar or metabolic concerns → Have you consulted a doctor / nutritionist first?

You don’t need to memorize this checklist. Stick it on the fridge or save it on your phone, and just glance at it before heading out. Once the habit forms, these judgments become second nature.

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Actionable Advice for Readers at Different Levels

Everyone starts from a different point, so I’ve divided the advice into three tiers. Pick the one closest to your situation and start there.

For Exercise Beginners / General Health-Conscious Individuals

• Daily life: Start with “reducing the sugar in your bubble tea”—that’s the change with the highest return on investment.
• Exercise: If you’re just walking, easy cycling, or running 30–60 minutes a day, plain water is enough—no special sugar replenishment needed.
• Mindset: Don’t demonize sugar to the point of fearing fruit or rice. Carbs are the body’s normal fuel; the key is to moderate added sugars.

For Advanced Enthusiasts (Those Challenging Long Distances with Regular Training)

• During exercise: Follow the dosage table above—aim for 30–60 grams per hour for 1–2 hour sessions, and start building your own replenishment rhythm.
• Gut training: Practice fueling during long-distance training; don’t wait until race day to test it.
• Diet periodization: Learn to adjust carbohydrate intake between “training days” and “rest days.”

Another Case Study: A Long-Distance Runner Who Used Sugar Correctly

Besides A-Zhe, who feared sugar, let me share a case in the opposite direction—a student who loves running, let’s call her Xiao-Min. Her problem wasn’t a fear of sugar, but a chaotic fueling rhythm. Before every half marathon, she’d nervously chug a large sugary drink right before the start, then cram two or three energy gels mid-race when hunger hit. The result: around the 15-kilometer mark, her stomach would churn and she’d feel nauseous, and her times stayed stuck.

The adjustment I made for her was actually simple: change “random cramming” to “planned, small amounts at frequent intervals.” We rehearsed it during training—eating an easily digestible meal 3 hours before the start instead of chugging right before the race; during the run, taking a small sip of energy gel with water every 30 to 40 minutes instead of waiting until she was starving and cramming it all at once. After a few weeks of gut training, her nausea almost disappeared, and she smoothly broke her personal record in the half marathon.

Xiao-Min’s case shows us: Many people’s fueling problems aren’t “too little” or “too much,” but “too erratic and too concentrated.” Small amounts, frequent intervals, and a plan—that’s what your gut can handle. This is why I always emphasize the importance of rhythm and rehearsal.

For Those with Health Concerns (High Blood Sugar, Metabolic Conditions)

I want to address this section with particular care. If your health check shows elevated blood sugar, abnormal HbA1c, or you’ve been told you have metabolic issues, please discuss any adjustments to your exercise fueling strategy with your doctor or nutritionist first.

• Exercise itself is usually beneficial for blood sugar management, but the type, timing, and dosage of sugar replenishment need to be individualized—you can’t just copy general advice.
• Taiwan’s NHI makes medical access convenient—use the resources: consult a family medicine or endocrinology clinic, or have a qualified nutritionist design a diet for your specific condition.
• If you’ve experienced palpitations, cold sweats, confusion, or other abnormalities during exercise, stop immediately and seek medical evaluation—don’t guess on your own.

For A-Zhe, my approach was to first have him return to the clinic and explain his blood sugar situation to the doctor clearly, then I helped him design a “control sugar daily, replenish moderately during exercise” strategy for different situations. Six months later, he not only completed his long-distance challenge, but the red flags on his health check also improved with the medical team’s help. The key has never been “cut sugar” or “eat sugar”—it’s using the right sugar at the right time.

Quick FAQ

Q: Energy gels, bananas, or sports drinks—which should I choose during exercise?
A: There’s no single right answer; it depends on your stomach and the situation. Energy gels are concentrated and easy to carry, but remember to drink water with them. Bananas are a natural, easily digestible option, suitable for low-to-moderate intensity. Sports drinks replenish carbs, water, and electrolytes at once, making them practical for long sessions. I recommend trying all three during training to find your combination.

Q: Is it okay to eat sweets after a workout?
A: In the short period after exercise, your muscles are more efficient at replenishing glycogen, so consuming a moderate amount of carbohydrates (paired with some protein) is reasonable. But that doesn’t mean you can eat without limits—your overall calorie intake and training volume still matter.

Q: Are low-carb/ketogenic diets suitable for endurance athletes?
A: This is a highly controversial and very individual topic. Some people train their fat utilization well for low-intensity, ultra-long distances, but for most endurance performance requiring high-intensity output, carbohydrates remain hard to replace. If you want to try it, I strongly recommend doing so under professional guidance rather than jumping into a long-term regimen on your own.

Q: Do children need sugar supplementation during exercise?
A: For typical children’s daily activities (play, short sessions), there’s no need for sports drinks or energy gels; water is sufficient. The WHO’s sugar reduction recommendations apply to children as well, and perhaps even more so. For long-duration, high-intensity youth competitive training, please consult professionals for an individual assessment.

Q: I’m trying to lose weight. If I take in carbs during exercise, will it cancel out the calories I burn?
A: It depends on the duration and intensity of your session. For just 30–60 minutes of light-to-moderate exercise, you don’t really need to supplement carbs—water is enough, and forcing extra fuel just adds unnecessary calories. But if you’re doing true long-distance, moderate-to-high-intensity training, taking in a moderate amount of carbs during the session is about maintaining the quality of “finishing the workout properly”—a workout you can’t complete or that falls apart will actually hurt your weight-loss results more. The key to weight loss is overall calorie balance and daily diet, not “starving yourself during exercise.” Keep your daily added sugars in check, but still fuel what your training needs—that’s the sustainable approach.

Q: Can I drink unlimited sugar-free diet beverages?
A: Artificial sweeteners indeed provide no calories and can help control added sugar intake. But “sugar-free” doesn’t mean “drinking unlimited amounts is the healthiest choice.” Developing a habit of needing everything to taste sweet isn’t ideal in the long run. My advice is to treat them as a transitional tool from full-sugar to less-sweet, with the ultimate goal of getting used to the simplest options like plain water or unsweetened tea.

Q: So is fructose good or bad? Supplement it during exercise, but reduce it in daily life—isn’t that contradictory?
A: This actually echoes the core of this article. When fructose is consumed during exercise and burned immediately alongside glucose, it’s a great helper for increasing absorption; but when consumed in large amounts daily (especially high-fructose corn syrup in sugary drinks), excess becomes a health burden. The same sugar plays completely different roles in different contexts—that’s why I keep emphasizing “timing.”

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Conclusion: Not an Enemy, Not a Miracle Cure—A Tool You Need to Learn to Use

Back to the opening question: Is sugar an enemy or fuel?

After years of coaching athletes, here’s what I’ve learned—sugar is neither an enemy to fear nor a miracle cure to consume endlessly; it’s a tool you need to learn to use. Used in the wrong context (excessive daily added sugar), it slowly erodes your health. Used in the right context (fuel during long-distance exercise), it saves you from bonking and protects your brain and performance.

True masters aren’t ascetics who “completely quit sugar,” nor are they sweet-toothed people who “accept everything.” They’re people who understand adjusting by context, timing, and activity level. What you need to do is keep your daily sugar intake in check and use sugar smartly for exercise.

Next time you’re hesitating in front of the convenience store’s fuel shelf, ask yourself two questions: “What’s the intensity and duration of the exercise I’m about to do?” and “Will this sugar be burned immediately, or is it just a craving?” Once you’ve thought through these two, you’ve found the balance.

After all these years of coaching, the one thing I want to leave you with is this: Stop asking “Can I eat sugar?” and start asking “Is this sugar useful to me right now?” Once you develop this way of thinking, you’ll find you’re neither scared into not eating by health headlines nor crashing during long distances because of poor fueling. This ability to “adjust by context and timing” is a skill that truly belongs to you and stays with you.

Wishing you just the right amount of fuel to carry you to the finish on every ride and every run. See you out there.

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This article is for educational purposes and does not replace individual diagnosis and treatment advice from physicians, physical therapists, or nutritionists. If you have concerns about blood sugar, metabolism, or other health issues, please seek medical attention and individualized assessment.

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References

• World Health Organization — WHO calls on countries to reduce sugars intake among adults and children：https://www.who.int/news/item/04-03-2015-who-calls-on-countries-to-reduce-sugars-intake-among-adults-and-children
• Precision Hydration — How much carbohydrate do athletes need per hour?：https://www.precisionhydration.com/performance-advice/nutrition/how-much-carbohydrate-carbs-athletes-per-hour/
• Gatorade Sports Science Institute — Dietary Carbohydrate And The Endurance Athlete：https://www.gssiweb.org/sports-science-exchange/article/dietary-carbohydrate-and-the-endurance-athlete-contemporary-perspectives

Related Reading

• Athlete’s Snack Strategy: Smart Snacking Between Training Sessions—Making Snacks Your Second Training Partner
• Blood Sugar Stability for Athletes: A Complete Guide to GI/GL, Meal Timing, and Practical Fueling
• The Science of In-Workout Fueling: How Many Carbs Per Hour? A Complete Practical Guide from 60g to 90g
• The Complete Carbohydrate Guide: The Primary Fuel for Endurance Sports—Types, Daily Needs, and Race-Day Fueling Strategies