Whether it’s distance running season, triathlon season, or multi-hour movement for other fitness and health goals, as training amps up, so should energy and nutrient intake! We’re covering the basics of nutrition for endurance training, including how to avoid the one big mistake many people make when signing up for their first endurance race. As a helpful primer, you can also check out our article on macronutrient needs for fitness.
Endurance racing and weight loss
I’ll get right to the number one mistake. Many people sign up for races with the goal of weight loss or as a means of weight maintenance after significant loss. In reality, training with weight loss as your main goal can compromise short and long term health. Racing is about performance.
To push the body to new limits, getting enough of the right nutrients – including caloric nutrients – is necessary. As sports dietitians, we often have clients come to us in the aftermath of poor fueling: low energy, injury, stress fractures, anxiety, and more. What can that all lead to? Lower overall activity in the end with the possibility of losing muscle or gaining more weight. High fitness levels aren’t about aesthetics, they’re measured by the capability of your cardiorespiratory and musculoskeletal systems.
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Bear in mind that adding intensity and duration to your normal workout routine may not influence nutrient needs significantly when training begins. As the weeks go by though and more workouts last over an hour, the impact can be immense if you aren’t eating enough carbs, enough times each day, and starting to include intra-workout fuel.
Why low calorie intake is bad for recreational athletes
It may be hard to wrap your brain around calling yourself an athlete. But, as I taught in my nutrition and sports nutrition college courses for years, an athlete is someone who trains for and participates in a sport. You may not be a professional, but the demands you’re putting on your body training recreationally along with everything else on your agenda requires not just more energy, but specificity in timing and nutrition. Having less than your body needs for basic functions and exercise each day adds up overtime to limit recovery, increase injury risk, suppress immune function, and reduce the ability to perform your best come race day.
If energy gaps are more significant, hormonal function can be disrupted in women, leading to loss of menstrual function and associated bone loss. These are two key symptoms of the female athlete triad. In either gender, data on Relative Energy Deficiency in Sport (REDS) shows that low energy availability impacts all areas of health negatively. For others, it may lead to binges in the evening or even the day after longer, harder training sessions.
Recognizing hunger as an athlete
To provide adequate nutrition for endurance training, it’s important to listen to the body’s hunger cues. When training though, it’s even more important to eat when it seems logical: before you burn the energy. This is referred to as “practical hunger”. Practical hunger is eating when you may not be physically hungry, but because it’s a time that eating is what’s best for your body. Since long duration and intense exercise can suppress hunger hormones, practical hunger is often important after exercise. Reaching for liquid carbs and protein means getting recovery nutrients at the right time and preventing excess hunger later. It may also be important immediately before or during exercise when easily digestible carbs can aid intensity and workout duration. You can check out more regarding pre and post workout snacking here.
For example, start your day with a tall glass of water and a carbohydrate rich breakfast that includes protein and fat. This sets you up to be fueled and hydrated before your workout even begins. If running out the door just after waking to exercise, have half a ripe banana or even a tablespoon of honey. If this makes you nervous because you’ve had GI problems while training or competing in the past, it’s likely that you need to train your gut just like the rest of your body!
>>>Pre-workout and post-workout snacks are crucial to support energy and recovery, but you’ll also need carbohydrates during runs lasting longer than an hour. When this is the case, you can choose salted dried fruit, sports drinks, sports gels, blocks, or honey.
Nutrition for Endurance Training Recovery
>>>While you may not want them pre-workout due to high fiber content, don’t skimp on fruits and veggies throughout the rest of the day. The vitamins, minerals and antioxidants in produce work together to enhance recovery. The more different colors you consume, the better. So, aim to eat the rainbow!
While all nutrients are important, two that I like to emphasize to protect your body are vitamin C and omega-3.
Vitamin C is an important immune nutrient and helps protect against oxidative stress. Studies show increased intake of Vitamin C may help prevent upper respiratory tract infections post-marathon or ultramarathon. Increase your intake of C with more citrus, peppers, kiwi, greens, broccoli and even potatoes!
The International Society of Sports Nutrition released a position stand in 2025 promoting the role of Omega-3 EPA and DHA in performance. By supporting healthy inflammatory responses, adequate omega-3 may improve muscle recovery, support joints, and protect the brain. To obtain more omega-3s, include fats from fish like salmon, mackerel, and sardines. If following a vegan diet, or with environmental wellness in mind, algal EPA and DHA omega-3 is a smart bet. You want to aim for at least 500mg/day. I recommend You Theory or Nordic Naturals algae omega to recreational athletes. For those who require 3rd party tested for sport products, Nordic Naturals has an NSF Certified for Sport option. Speak with your doctor or dietitian to choose one that’s best for you.