Top 5 Nutrition Tips for Swimrun

This is a guest article from Dr Greg Potter, PhD, Chief Science Officer at Resilient Nutrition. Greg has coached athletes to gold medals and World Records in multiple sports, and he contributes to various media outlets, including Healthline, The Metro, The Mail, and Stylist Magazine. 

Swimrun is a tough sport. It is easy to get dehydrated and even easier to bonk, here are five helpful tips from Greg on fuelling well and maintaining your long term health.

Photographer: James Mitchell
  • Fuel for the work required.
    • You should manipulate your diet — your carbohydrate intake, especially — according to the activity you’re doing. If, for instance, you’re doing a hard session of intervals at race pace or faster and want to prioritise your performance, you should have plenty of carbohydrate in your pre-training meals and snacks so you start the session with full muscle carbohydrate (glycogen) stores.
    • If, however, your session is a lower-intensity workout at a relatively fixed pace, you might want to “train low”, restricting your carbohydrate intake around the session so that you stimulate adaptations in your body.This principle is also relevant to your health: If you consistently eat and drink to meet the physical demands of training and competition, you’ll meet your energy and nutrient needs, reducing the likelihood of experiencing common problems such as relative energy deficiency in sport, a syndrome in which not regularly consuming enough calories and carbohydrate leads to a variety of health and performance issues, including impaired reproductive function and increased risk of bone fractures.
  • Practice your nutrition in training. Your race performance depends in part on your in-race nutrition. The problem is that while you’re swimming and running your ability to digest and metabolise foods is compromised by a variety of changes in your body, including diversion of blood flow away from your gut towards your muscles and increased activity in the “fight or flight” branch of your autonomic nervous system. The good news, however, is that you can train yourself to take in more food and fluid during exercise. To do so, it’s best to do a minimum of 6 nutrition-training sessions over at least 2 weeks, slowly increasing the number of calories you consume per hour from one session to the next. For instance, if you can comfortably take in 40 g carbohydrate per hour at first, you might try to bump this up by 5 g per hour each session — so session 1 would be 40 g per hour, session 2 would be 45 g per hour, 3 would be 50 g per hour, etc. During such training, it’s best to use the exact foods and drinks you’ll use in competition, and the more you can mimic race conditions (e.g., pace, terrain, time of day), the better.
  • Choose easy-to-digest items before and during events. Digestive problems are one of the main causes of poor performance at races. You can minimise the probability of experiencing them through simple nutrition changes from about 24 hours before a race until the event is over. For some people, switching to a low-fibre diet is enough to do the trick. Others need to be more restrictive, limiting intake of all so-called FODMAPs, short-chain carbohydrates that are readily fermented by microorganisms in the gut, causing gastrointestinal distress. For more on how to eat around events, be sure to download this free guide to how to fuel for distance running. The guide focuses on ultra running, but the same principles apply to swimrun events. It is worth noting that you are often at the mercy of swimrun aid stations, so worth checking with the organisers what nutrition they will be providing.
  • Base your diet on whole foods. Many endurance athletes focus heavily on certain aspects of nutrition, such as consuming adequate amounts of carbohydrate. To meet their nutrition targets, they end up consuming heroic amounts of heavily processed foods, and over time this can catch up with them. While heavily processed items such as carbohydrate gels have their place in performance nutrition, we must remember that for well over 90% of human history people have relied on whole foods such as meat, fish, seafood, eggs, nuts, seeds, vegetables, fruit, and funghi. This means our bodies are best adapted to consuming these foods, so if you want robust health, your nutrition should reflect human history. For more on the general principles of how to eat well, check out this free e-book.
  • Don’t sacrifice your health at the expense of your performance. Related to previous points, many athletes get so wrapped up in their performance and body composition that their health begins to slide. Sure, there are times of year when you might decide that performance is a priority over health, but this should not be true year round. You can’t always be in race shape, and having phases when you give yourself a mental and physical break is key to maintaining your long-term health and enthusiasm. Within reason, don’t be afraid to reduce your training loads and loosen your belt buckle following competitions.