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The role of fat in the western diet is complicated, at best. As is the case with most nutrition standards, what is considered to be healthy has changed dramatically over time. From the rise in fast-food to the fat-free movement, the obsession with avocados (U.S. consumption has tripled since 2001), the Mediterranean diet, and now keto (which is both praised and put down), there’s a lot of conflicting advice to manage.
In general, we know that fat is important for a healthy immune system, endocrine function, and absorbing vitamins A, D, E, and K. It also makes us feel full and satisfied from meals. But for a runner’s body, it is especially important in kick-starting the muscle recovery process.
During recovery, the fat that is available in the blood is increased. This fat inhibits the breakdown of glucose and, through mechanisms that are not fully understood, makes sure that post-exercise carbohydrates are directed towards re-synthesis, rather than breakdown. “The fat is oxidized to reserve the ingested carbohydrates for rebuilding glycogen stores in the muscles,” explains Bente Kiens, PhD, a professor of molecular physiology at the University of Copenhagen.
In recent research conducted by Kiens and her team, they showed the prevalence of fatty acids in the blood peaked directly after exercise was complete, with a gradual decline in the following four hours. And some of the fat content was still present up to 24 hours after exercise in some cases. “All together, this increased availability of fat to the muscle will stimulate fat oxidation and enable glycogen resynthesis from the available dietary carbohydrates,” says Kiens.
This happens utilizing stores of triglycerides in the body, which means there’s nothing that you necessarily need to do to start the process post-run. “Unless you are immuno-compromised, starving (on a low-energy diet), or an ultra-endurance athlete, there is little-to-no justification for consuming fatty acids post-exercise,” says exercise physiologist and NASM certified personal trainer and nutritionist, Fabio Comana.
The average runners should be consuming the recommended 25 to 35 percent of kcals from fat for daily function and to build up those stores. “There are some athletes who adapt to a much higher fat diet and report good outcomes,” says Michelle Rockwell, PhD, RDN, and an instructor in the department of human nutrition, foods, and exercise at Virginia Tech. For runners who are adjusted to the keto diet, 75 to 85 percent of their daily kcals will come from fat. But consuming too little fat on a daily can be detrimental to your health and fitness.
“Athletes should strive to avoid a body fat percentage that is too low,” says Julie Stefanski, RD, certified specialist in sports dietetics and spokesperson for the Academy of Nutrition and Sports Dietetics. “This can impact the availability of fatty acids for recovery that are being drawn from tissue stores.” An extremely low-fat diet or body composition also leaves runners vulnerable to reproductive issues and compromised immune systems.
“The best recovery diet would be to prioritize carbohydrates, especially those with a moderate to high glycemic index, not too many proteins, but rather some fat to secure adequate energy to be able to be in energy balance as soon after the exercise as possible,” says Kiens.
Omega-3s May Speed Up Muscle Recovery
Omega-3s are a bit of an exception, and should be prioritized in some manner because they are crucial for muscle recovery. Several studies have shown that taking fatty-acid and fish oil supplements reduces soreness, improves neuromuscular function, and, in the case of one study done on rugby players, an increase in fatty acids helped build explosive power.
It is also the case that most people do not get enough omega-3s in their diet. In a paper published in PLOS ONE, a group of researchers looked at how collegiate athletes consumed the essential fatty acid. “A big picture takeaway of this study is that most collegiate athletes consume insufficient dietary omega-3s, especially EPA [eicosapentaenoic acid] and DHA [docosahexaenoic acid], the specific omega-3s most associated with inflammation, recovery, and brain health,” says Rockwell, who was one of the researchers on that paper. In the analysis, only 6 percent of the participants consumed the 500mg of EPA and DHA recommended by the Academy of Nutrition and Dietetics.
“Fat is also not typically emphasized in the recovery period since the emphasis is on rehydrate, rebuild, replenish, fluids/electrolytes, protein, carbohydrates. Too much fat could displace these other nutrients,” says Rockwell. “However, there is some evidence that [omega-3] fats in particular could play an important role in reducing inflammation in the post-exercise period and make muscles more receptive to protein, thereby improving recovery and remodeling.”
According to Rockwell, it can be pretty challenging to get those recommended omega-3s, because very few foods actually contain them. Fish and other seafood are the best sources. Algae, flax seeds, chia seeds, and walnuts contain ALA [alpha-linolenic acid] that the body converts to EPA and DHA on a very small scale. Some research shows that only around 8 percent of ALA is converted to EPA and 4 percent to DHA.
If you are looking to incorporate more omega-3s into your diet, Rockwell says that after a run is a great time to consume them, alongside protein and carbohydrates.
An argument could be made to reduce some other fats to get the maximum benefits from omega-3s. “We talk a lot about the omega-6:omega-3 ratio,” says Rockwell. “However, when we consume a lot more [omega-6s] than [omega-3s], the balance of pro-inflammatory to anti-inflammatory may be disturbed.” Nuts, seeds, oils, and processed foods are sources of omega-6 fatty-acids.
However, all the experts we spoke with emphasized that there’s no need to overcomplicate the recovery process in regard to diet. “I prefer to help athletes think about whole foods and everything they get from them rather than specific nutrients. For example, salmon is not only a great source of omega-3s, but of vitamin D as well,” says Rockwell.
“It’s really important to listen to your own hunger level and refuel your body as it requests to maximize recovery,” says Stefanski.