Most runners who aren’t seeing gains are training hard enough. They’re just not eating in a way that lets the training land.

Alex Larson is a Minnesota-based registered dietitian who works with endurance athletes on fueling for performance and body composition. She has worked with athletes across 15 countries and has completed 20-plus triathlons including Ironman Wisconsin, which is where the whole thing started. She crossed that finish line watching people suffer through cramping and bonking and realized how many performances fell apart due to nutrition, not fitness.

This conversation covers daily nutrition structure, carb timing, in-run fueling guidelines, what supplements are worth taking and what are not, and the fast way that eating better earlier in the day changes how you sleep.

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The most common mistake Larson sees: athletes map out their training with precision and then eat whatever is convenient around it. That is backwards.

Fitness gains do not happen during the workout. They happen in recovery, which takes hours or days for endurance athletes and is powered almost entirely by nutrition. Even an easy long run is taxing on joints, muscles, ligaments, and tendons, and the energy required to rebuild from that is routinely underestimated.

Larson structures her athletes' nutrition in two buckets: fueling around the workout itself, and optimizing recovery nutrition throughout the rest of the day. The second bucket is where most people have the bigger gap, and where the consistent fitness gains actually come from.

The pattern Larson sees repeatedly: athletes train in the morning, eat a small breakfast and a light lunch, get ravenous in the afternoon, and then eat the majority of their calories between mid-afternoon and bedtime. The body spends the night digesting and processing rather than recovering and resting.

The fix is front-loading. Get 75 to 80 percent of your daily nutrition targets in before dinner. That means a real breakfast before or shortly after your morning run, a substantial lunch, and afternoon snacks that keep you out of the starving-by-3pm hole. By the time dinner arrives, it is a reasonably sized meal rather than a gorge session, and by bedtime the body is in a low-stress, non-inflamed state that supports actual sleep.

Larson hears the same thing from athletes within two weeks of making this shift: sleep quality improves noticeably, often dramatically. The mechanism is straightforward. Under-fueling creates physiological stress and inflammation on top of the stress of training. Remove the under-fueling, move the calories earlier in the day, and the body can do what sleep is supposed to do.

For a run starting one hour after waking, the goal is easy carbohydrates that digest quickly. Larson's options: applesauce pouch, graham crackers, a Pop-Tart, an Eggo waffle with syrup, a bagel with a small amount of peanut butter, or a sports drink if solid food is not happening. Low fiber, low fat, easy to digest. Carbs are the fuel, not protein and vegetables, which are harder to process and can cause GI issues mid-run.

If you have 90 minutes to two hours, there is room for a more complete meal. Add protein around 20 grams and slightly more volume: oatmeal with milk, cereal with milk, eggs with toast. Still keep fiber and fat relatively low.

The athlete who never eats before morning runs and is wondering why workouts feel hard has found the problem.

For workouts under 60 to 75 minutes, zero to 30 grams of carbs per hour is appropriate, assuming solid pre-run fueling. If pre-run fueling was light or skipped, Larson recommends going above that range even for shorter sessions.

Above 75 minutes, shift to 30 to 60 grams per hour. Higher intensity sessions with interval efforts warrant the top of that range even at 90 minutes to two hours. Above two and a half hours, 60 to 90 grams per hour is the target. The very top end (the 100-plus grams some elite athletes use) requires gut training and significant individual tolerance work.

The variables that adjust all of this: how well you fueled the day before, whether the weather is warmer than usual, how you are feeling at the start. Larson teaches her athletes to read these inputs and adjust rather than rigidly hitting a target number regardless of context.

Creatine is the clearest yes. Decades of research, strong safety profile, meaningful benefits for muscle maintenance and recovery, and particularly important for athletes over 40 and for plant-based athletes who get less creatine through diet. Larson has been taking it since 2023 and reports better bounce-back from workouts. Creatine monohydrate powder over gummies: independent testing has found roughly half of gummy brands under-deliver on stated dosage. Look for NSF Certified for Sport or Informed Choice for Sport.

Protein powder is worth having for athletes with high protein needs who struggle to hit targets through food alone. Whey isolate or a plant-based blend with multiple protein sources.

Collagen is mixed in the research. Some evidence for joint and connective tissue benefit. The useful timing detail: take it 40 to 60 minutes before exercise. Increased blood flow to joints during movement may improve absorption. It will not harm you regardless.

Ketones for athletic performance are not worth it. Research does not show consistent benefit, some studies found decreased performance, and the products are expensive and taste bad. If you want an energy source for your run, take carbs.

Larson has seen a small but growing number of endurance athletes using GLP-1 medications for weight loss. She is not opposed, but she is realistic about what it actually requires.

Her framework: work with a sports dietitian first to build a nutrition foundation. Start in the off-season, never during a training block. Get a DEXA scan before starting and repeat every three months. Keep strength training consistent. Have an exit plan.

The version that goes wrong is an athlete who takes the medication, loses weight quickly without monitoring body composition, loses significant muscle mass, and then wonders why performance declined and injury risk went up. The weight changed but the outcome was not what they wanted.

Larson tested ChatGPT's calorie recommendations on herself and found it recommended 200 to 500 calories above her own calculation. She has seen it recommend 1,800 calories for a triathlete training 15 hours a week, roughly a thousand calories short of what that athlete needed.

The useful applications are narrow: meal ideas around a protein target, a fueling plan for a long run as a starting point to modify, inspiration when decision fatigue hits. Not useful: treating any output as a personalized recommendation or a substitute for an actual nutrition assessment. The individual nuance required to get this right does not exist in a general prompt.

Front-load your nutrition to protect sleep and recovery: Getting 75 to 80 percent of your daily nutrition in before dinner keeps your body out of a stressed, inflamed state at night. Athletes who make this shift often report noticeably better sleep within two weeks.

Recovery nutrition is everything you eat outside the workout: The energy required to recover from even an easy long run is significant and takes hours. What you eat at lunch and dinner on training days matters as much as what you take on the run.

Low fiber, low fat, easy carbs before morning runs: An Eggo waffle, a Pop-Tart, a bagel with a little peanut butter. The goal is quick-digesting energy. Save the vegetables for later in the day.

Creatine monohydrate powder, not gummies: The research is strong and the safety profile is excellent. Gummy formats have inconsistent dosage delivery. Three to five grams daily, look for third-party certification.

Ketones are not worth the money for athletic performance: The research does not support the investment, some studies showed decreased performance, and the products are expensive and taste bad. Take carbs instead.

GLP-1s for athletes require real infrastructure: DEXA scans before and throughout, sports dietitian involvement, off-season timing, consistent strength training, and an exit plan. Athletes who skip this step often lose muscle mass that costs them on the back end.

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Jon is a runner, cyclist, and podcast host from Boston, MA, who now lives in Boulder, CO. For The Long Run is aimed at exploring the why behind what keeps runners running long, strong, and motivated.

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