Fuel for the work you're about to do, not the work you did.

Bonking is a planning problem, not bad luck. Build the whole ride hour by hour, watch your carbohydrate stores rise and fall, price up a bottle and gel plan that won't empty your wallet, and dial in your sweat and salt. Eat enough, train the gut, and let the back half of the ride look after itself. Saddle up.

Session

Whole-Ride Fuel Planner

Plan the entire ride, not just an hour of it. Set the duration and intensity and this builds an hour-by-hour plan of carbs, fluid and sodium, shows your glycogen tank draining against what you take on, then prices it up and prints a schedule you can tape to your bars.

Carbohydrate is the limiter at intensity. You store roughly 90 minutes to two hours of it, so anything longer means topping up. Targets scale with duration: under an hour rarely needs fuel, one to two hours wants 30 to 60 g/h, two to three hours 60 to 90 g/h, and beyond that 90 to 120 g/h with a dual glucose-to-fructose source and a trained gut. Fluid replaces sweat; sodium replaces what is lost in it. Burke, Hawley and Jeukendrup (2011); Podlogar and Wallis (2022).

Ride totals

Glycogen tank: fuelled vs unfuelled

Hour by hour

Schedule card

Fuel it: build your combination

Mix products the way you actually ride: a bottle base plus gels, or a single brand. Add items and watch the bar fill to your target.

Drink mix Gel Chews/bars Real food DIY

Carb Loading (before)

For events over about 90 minutes, topping up muscle glycogen in the 24 to 48 hours beforehand pays off. This sizes the daily carbohydrate target for the load phase.

Recovery (after)

The hours after a hard or long ride set up the next one. This gives the rapid-refuel carbohydrate and protein, plus fluid replacement from how much you lost.

Daily Macronutrients

Match the day's intake to the day's training. Targets are set per kilo of body weight, referenced against your resting needs, and the carbohydrate scales with how hard you ride. Fuel for the work required.

Resting metabolic rate (Mifflin-St Jeor) is the floor, not a target. Energy availability should sit comfortably above it to support adaptation and health. Carbohydrate is periodised to the session because it is the fuel that runs short; protein supports repair at roughly 1.4 to 2 g/kg spread across the day; fat covers the rest of hormonal and metabolic need. Under-fuelling, not over-fuelling, is the common error in endurance sport. Burke, van Loon and Hawley (2017); Vitale and Getzin (2019).

Energy split

Fuelling check: are you eating enough?

This screens energy availability, a marker of whether your intake covers both training and the basic running of your body. It only ever points one way, toward fuelling more. It is not a diagnosis and never a reason to eat less.

What is RED-S, and the signs to watch
RED-S (Relative Energy Deficiency in Sport) is what happens when you do not eat enough to cover training plus normal body function over time. It harms performance and health, including bones and hormones. Warning signs include poor recovery, recurrent illness or niggling injuries, stress fractures, always feeling cold or flat, low mood, disturbed sleep, and changes to or loss of periods. The fix is always more fuel, not less, and if any of this sounds familiar it is worth speaking to a GP or a registered sports dietitian. For younger riders, growth raises needs further, so adequate fuelling matters even more.

Sweat Rate Test

Weigh yourself before and after a measured ride, in minimal clothing, and log everything you drank. This returns your sweat rate, which feeds your fluid and sodium targets in the planner. Test in conditions like your event, since rate climbs in the heat.

Not sure on sodium? If your kit is crusted white after rides, your eyes sting, or sweat tastes very salty, pick a higher band. A lab patch test gives the exact figure.

Products & Cost

Every option compared on the only fair measure, cost per 100 g of carbohydrate. Filter by form, sort any column. A homemade mix undercuts the branded gels many times over.

Drink mix Gel Chews/bars Real food DIY
Prices are indicative UK RRP and move often. Treat them as a guide.

Bottle Mixer

Make your own bottle to a target. Enter the carbs you want and the ratio, and it gives the powder to weigh, plus a salt dose and a concentration check.

The short version

Carbohydrate

Your body stores roughly 90 minutes to two hours of hard riding as glycogen. Past that you fuel or you fade. Aim for 30 to 60 g/h up to a couple of hours, and 90 to 120 g/h for long, hard days, using both glucose (maltodextrin) and fructose so you absorb more than glucose alone allows. The gut adapts to this, so build it in training.

Protein

Around 1.4 to 2 g/kg across the day supports repair and adaptation, best spread over meals rather than taken in one hit, with roughly 0.3 g/kg after hard sessions.

Fluid and sodium

Replace what you sweat. Measure your sweat rate rather than guessing, and match sodium to how salty your sweat is. Losing more than about 2 to 3 percent of body mass to dehydration costs performance.

Fuel for the work required

Big days need big carbohydrate. Easy days need less. Periodising intake to the session, rather than eating the same every day, supports both performance and a healthy energy balance. The common mistake in endurance sport is taking on too little, not too much.

Cost

Branded gels are convenient but expensive per gram of carbohydrate. A homemade maltodextrin and fructose mix, or even bananas and jam sandwiches, fuels you for a fraction of the price. Use the Products tab to see the gap.

References

Baker, L. B. (2017). Sweating rate and sweat sodium concentration in athletes. Sports Medicine, 47(Suppl 1), 111-128.

Burke, L. M., Hawley, J. A., Wong, S. H. S., & Jeukendrup, A. E. (2011). Carbohydrates for training and competition. Journal of Sports Sciences, 29(sup1), S17-S27.

Burke, L. M., van Loon, L. J. C., & Hawley, J. A. (2017). Postexercise muscle glycogen resynthesis in humans. Journal of Applied Physiology, 122(5), 1055-1067.

Jette, M., Sidney, K., & Blumchen, G. (1990). Metabolic equivalents (METS) in exercise testing. Clinical Cardiology, 13(8), 555-565.

Mifflin, M. D., et al. (1990). A new predictive equation for resting energy expenditure. American Journal of Clinical Nutrition, 51(2), 241-247.

Podlogar, T., & Wallis, G. A. (2022). New horizons in carbohydrate research and application for endurance athletes. Sports Medicine, 52(Suppl 1), 5-23.

Veniamakis, E., et al. (2022). Effects of sodium intake on health and performance in endurance sports. IJERPH, 19(6), 3651.

Vitale, K., & Getzin, A. (2019). Nutrition and supplement update for the endurance athlete. Nutrients, 11(6), 1289.

Guidance for healthy adult athletes, not medical or dietary advice for individuals. Aim to fuel enough for the work you do; under-fuelling carries real risks. Questions: ride@saddleupcycling.co.uk