What's the difference between sports nutrition and just eating food during exercise?

The difference is absorption speed and GI tolerance. A banana has ~27g of carbs, but it also has fiber, fat, and protein that slow gastric emptying. During intense exercise, blood is diverted away from the gut (splanchnic hypoperfusion), making solid food digestion unreliable and often nauseating. Sports drinks and gels are engineered to bypass these limitations — they use specific sugars that absorb rapidly through dedicated intestinal transporters, in concentrations that clear the stomach quickly. At low intensities (easy hikes, Zone 1-2 training), solid food works fine. At high intensities or durations beyond 2 hours, purpose-formulated liquid nutrition is significantly more reliable.

What are the advantages and disadvantages of gels vs. drinks?

Drinks combine fuel, fluid, and electrolytes in one package — simple to manage and they hydrate simultaneously. The downside: you can't increase one without increasing the others. If you need more sodium on a hot day, you drink more, which means more carbs (potentially exceeding absorption limits). Gels are concentrated carb boluses taken separately from hydration. Advantages: precise fuel dosing independent of fluid intake, portable, and you can adjust your hydration separately. Disadvantages: they require chasing with water (or you get a concentrated sugar mass sitting in your stomach), and the texture/sweetness can cause fatigue over long events. Most elite athletes now use a combination: a moderate drink mix for baseline hydration + sodium, with gels for additional fuel as needed.

How are sports drinks better than just having a Coke?

Coke is ~11% sugar (HFCS-55 in the US, sucrose elsewhere), which exceeds the 8% gastric emptying threshold — at race intensity, it empties too slowly to keep up with what you're drinking. It also has minimal sodium (~45mg per 12oz vs. 200–400mg in a real sports drink serving), which means it doesn't drive intestinal water absorption. A well-formulated sports drink is 6-8% carbs with 200-400mg sodium per serving, in a glucose:fructose ratio optimized for dual-transporter absorption. Flat Coke diluted 50/50 with water and a pinch of salt would actually be a reasonable improvised sports drink — it's the concentration and sodium that matter, not the brand. At that point, you're rebuilding what the builder does — just by hand.

How many grams of carbs per hour should I consume?

It depends on duration and intensity. For efforts under 60 minutes, you generally don't need exogenous carbs — your glycogen stores are sufficient. For 1-2 hours at moderate intensity, 30-60g/hr is a good range. For 2-4+ hours or high-intensity efforts, 60-90g/hr with a dual-transporter formulation (glucose + fructose). Elite athletes with trained guts push 90-120g/hr using optimized 1:0.8 ratios. But none of this works without gut training. Start at the lower end and increase by 10-15g/hr per week over several training blocks. Jumping straight to 90g/hr without gut training is a recipe for GI disaster.

Do I really need all those electrolytes, or is sodium enough?

Sodium is the priority. With chloride, it makes up about 90% of sweat electrolyte mass (sodium alone is ~37%), and it's the only electrolyte that directly enhances intestinal water and glucose absorption (via the SGLT1 co-transporter). Potassium and magnesium losses in sweat are much smaller — sweat carries roughly 4-6× more sodium than potassium, with magnesium around 12 mg/L — and no RCT has shown that adding them during exercise improves performance. That said, they're cheap (about 1¢ per serving) and harmless at typical doses, so there's no downside to including them if you prefer. Many commercial products do. If you do include them, we default to potassium chloride for K (cheap, highest elemental fraction, the form LMNT and Tailwind use) and magnesium malate for Mg (LMNT's form, slightly higher elemental density than citrate, clean taste at sports-drink doses). Magnesium citrate works equally well if it's what you already have. Don't skip sodium. Everything else is optional.

What is gut training and do I need to do it?

Gut training is the practice of progressively increasing carbohydrate intake during training sessions to improve intestinal tolerance and absorption capacity. Research shows that GLUT5 (the fructose transporter) upregulates with repeated exposure — your gut adds more transporter machinery the more you train it. If you've been eating gels at 40g/hr and want to race at 90g/hr, you can't just flip a switch on race day. Start by adding 10-15g/hr to your training fueling every 1-2 weeks. Practice with the exact products and concentrations you'll use in competition. Most GI distress in races comes from under-practiced fueling strategies, not from the products themselves.

Is it safe to mix my own sports drinks? Will it be as effective?

Yes — the active ingredients are the same regardless of whether you buy a branded product or mix bulk powders. Maltodextrin, fructose, and table salt are food-grade commodity ingredients available from any bulk supplement supplier. The physiology doesn't care about packaging or branding — it cares about the concentration of specific sugars hitting specific transporters at specific rates. The one caveat: measure carefully. A kitchen scale accurate to 1g is essential. Too much powder in too little water crosses the 8% concentration threshold and defeats the purpose. Follow the same ratios and concentrations that the commercial products use, and the results are physiologically identical.

Why use maltodextrin instead of regular sugar?

Maltodextrin is a glucose polymer — typically 3-20 glucose units chained together. It delivers glucose to your muscles at the same speed as free sugar (amylase enzymes break it down almost instantly), but with a fraction of the osmotic pressure. This means you can pack more energy into a solution without exceeding the gastric emptying threshold or causing osmotic diarrhea. It's also nearly tasteless (0.1x the sweetness of sucrose), which eliminates the 'flavor fatigue' that makes sugary drinks increasingly unpleasant over multi-hour events. The downside: it only provides glucose (SGLT1 pathway), so you still need a fructose source to activate the GLUT5 pathway.

When during exercise should I start fueling?

Start early — ideally within the first 15-30 minutes of exercise for any effort that will last beyond 60-90 minutes. It takes time for ingested carbohydrates to transit the stomach, get absorbed in the small intestine, and appear in the bloodstream. If you wait until you feel depleted to start fueling, you're already 30-45 minutes behind. A common strategy: begin with a smaller bolus (20-30g) in the first 15 minutes, then maintain a steady intake every 15-20 minutes thereafter. By the time you're deep into an event, you want a consistent stream of exogenous fuel arriving — not playing catch-up from a deficit.

How do I make my DIY mix taste better without hurting performance?

Every flavoring agent you add contributes to osmolality, competing with your fuel for osmotic budget. At high carb loads (90+ g/hr), this tradeoff is severe — which is why Maurten is unflavored. The lowest-impact option is 1-2 drops of food-grade essential citrus oil, which adds intense perceived flavor via olfaction with literally zero osmolality. For moderate loads (60-80 g/hr), citric acid (1-2g) and malic acid (0.25-0.5g) provide tartness. For lower loads, freeze-dried fruit powder gives authentic flavor. See our full flavoring guide at /flavoring for five strategies with dosing and an ingredient reference.

Sports drink & DIY fueling FAQ

The most common endurance-fueling questions, answered in plain English. Each answer links to the physiology behind it — verify the claim, push further if you want.

Want the model behind these answers?

Each answer traces back to the same three variables — transporters, osmolality, gastric emptying. How-it-works walks through the design logic. Science is the citation layer if you want to verify a specific claim.

How sports drinks work The science reference Build my mix