I’ve crashed hard on a few long rides and learned the hard way that “bonking” isn’t just about running out of energy — it’s about getting the right carbs in at the right time without upsetting your stomach. Over the years I’ve refined a simple, practical plan that balances carbohydrate quantity, variety, and timing to keep power up for rides over three hours while minimizing gastrointestinal pain. Below I share what works for me and for the athletes I coach, with concrete numbers, snack ideas, and a ready-to-use schedule you can adapt and test on training rides.

Principles I follow to avoid bonking and GI distress

Before getting into specifics, here are the rules I rely on:

  • Prioritize carbohydrate amount per hour — for long rides I aim for roughly 60–90 g of carbs per hour. That’s a range: how much you choose depends on intensity, body size, and how well your gut tolerates carbs.
  • Use multiple carbohydrate types — combining a glucose-based carb (maltodextrin, dextrose) and fructose in a ~2:1 ratio increases absorption and lowers gut stress. Many modern sports drinks and products are formulated this way.
  • Keep pre-ride food low in fiber and fat — fiber and fat slow gastric emptying and often cause discomfort. I stick with easy-to-digest carbs in the 1–3 hours before a ride.
  • Hydrate and include sodium — fluid and electrolytes help intestinal function; low-sodium or plain water-only strategies can increase GI issues for some riders.
  • Test on training rides — what works in a 4-hour weekend ride may not work during race week. I always practice the exact foods and timing I’ll use on race day.

    • Pre-ride: what and when to eat

    My pre-ride routine aims to top up glycogen without gurgly guts. Timing and portion size matter:

  • 2–3 hours before a long ride: 0.5–1.0 g of carbs per kg bodyweight. For a 70 kg rider that’s about 35–70 g carbs. I usually eat closer to 0.7–0.8 g/kg if I have time — e.g., a bowl of porridge with a banana or a white-bread bagel with honey. Low fibre, moderate protein (10–15 g) is OK if it sits well with you.
  • 30–60 minutes before: a small top-up of 15–30 g fast carbs if needed — a small energy gel, half a banana, or a carb drink. This helps for rides starting with high intensity and avoids fullness.

    • Examples I personally use:

  • 2 hours out: 60 g rolled oats made with water + a tablespoon of jam (approx. 50 g carbs) plus a small banana.
  • 30 minutes out: 20–25 g quick carbs (half a gel or a small chew) with water.

    • On-ride carbohydrate dosing and snack schedule

    For rides >3 hours, I aim for a steady stream of carbs rather than big infrequent snacks. Here’s the practical hourly goal I use and recommend testing:

  • Low-mid intensity aerobic rides: 60 g carbs/hour is usually adequate.
  • High intensity or long sustained efforts: 75–90 g carbs/hour, ideally via multiple transportable carbs (glucose + fructose).

    • How I split those carbs across the hour:

  • Every 15–20 minutes: 15–25 g carbs (small gel, a few chews, or 200–300 ml of a 6–8% carb drink).
  • Alternate solid and liquid if your stomach tolerates it: for example a gel at :00, a small bar at :20, and a drink at :40.

    • Practical 4-hour ride schedule (example)

    Below is a schedule I use on 4-hour rides. It keeps carbs steady, mixes forms, and includes electrolytes. Adjust grams by body size and intensity.

    Time Item Carbs (g) Notes
    -2:00 Oat porridge (small) + jam + banana 50–60 Low fibre version; gives glycogen top-up
    -0:30 Small gel or 250 ml carb drink 20–25 Rapid carbs without bulk
    0:00 (start) Electrolyte/carb bottle (6–8% maltodextrin + fructose) ~20 Sip through first 20–30 minutes
    0:20 Gel (or 3–4 gummies) 20–25 Glucose + fructose gels are best
    0:40 Small energy bar or rice cake 15–25 Chewable carbs to feel “real food”
    1:00 Refill bottle / electrolyte sip 10–20 Continue sipping between feed points
    1:20 Gel or chew 20–25 Repeat pattern every 20–30 min
    1:40 Small sandwich or flapjack (if tolerated) 20–30 Optional “real food” moment
    2:00–4:00 Repeat cycle (drink + gel/chew + small solid every hour) 60–80 per hour Adjust based on effort and stomach

    Foods and products I trust (and why)

    I use a mix of drinks, gels, and chewable carbs because variety helps hit carb targets without overloading the gut:

  • Carb drinks: Tailwind Endurance, SIS Beta Fuel, or a DIY maltodextrin + fructose mix — these give steady carbs and electrolytes.
  • Gels: GU, Maurten Gel, or SIS Go Isotonic — especially formulations that combine glucose and fructose.
  • Chews and gummies: Clif Bloks, Huma, or Science in Sport chews — good for small frequent doses.
  • Real foods: rice cakes, low-fiber flapjacks, white-bread sandwiches with jam or honey — use these sparingly and only if you know your gut tolerates them.

    • Tips to minimize GI pain

    Preventing GI upset is as important as hitting carb numbers. These are the practical tweaks that helped me enormously:

  • Avoid high fiber/fat pre-ride meals within 3 hours of starting. No big beans, no greasy breakfast, no large chia puddings.
  • Keep drink concentrations sensible — around 6–8% carbs (60–80 g per liter) is comfortable for many riders. Very concentrated drinks (>10%) can slow gastric emptying and cause nausea.
  • Sip frequently instead of downing large volumes. Small, steady sips maintain gastric flow.
  • Spread carbs across 20–30 minute intervals instead of stuffing 60 g at once. Your gut handles repeated small doses better.
  • Use multiple transportable carbs (glucose + fructose) to increase total absorption and reduce leftover glucose sitting in the intestine.
  • Warm weather strategy: lower solid intake, increase dilute carb drink. Hot conditions slow digestion of solids for many people.
  • Train your gut — over weeks you can increase your tolerance to both volume and carb rate by practicing during training rides.

    • How I tweak numbers for body size and effort

    Carbohydrate needs scale with size and power output. As a quick rule of thumb I use:

  • Smaller/lighter recreational riders: start at 60 g/hr.
  • Average club riders: 60–75 g/hr.
  • High-power or long-competitive riders: 75–90 g/hr, split across glucose + fructose.

    • And if you’re doing consistent high-intensity intervals or racing, err on the higher end. For steady aerobic tempo, you can be comfortable at the lower end.

    Finally, remember that there’s no single perfect plan — only the plan you’ve practiced until it becomes automatic. Test different gels, drinks, and timings on long training rides, note what triggers reflux or cramps, and adjust. Do that, and you’ll show up to that >3-hour ride fueled, comfortable, and ready to enjoy the miles.