Timing Meals for Endurance and Strength Athletes

Glycogen Replenishment, Polyphenols, Timing Meals

Introduction

So as we know there are 3 main macronutrients…carbs, fats, and proteins. Each have a calorie composition to it. Carbs has 4 cal/gram, Protein has 4 cal/gram, and Fats has 9 cal/gram. 

I often would get questions from clients, though, when to eat what and how much of it to eat. I think a lot has to do with how well your body naturally digests the food so let’s keep that in mind. 

I have linked some research papers that are useful and interesting, but this discussion is a slight summary of the finds. 

Glycogen Replenishment

First let's dive into what the benefits are the traditional “post workout” meal? Being a skeptic, it was a nice surprise to find that their is a sweet spot of a eating window post training that is worth taking advantage of, for hypertrophy training:

A primary goal of traditional post-workout nutrient timing recommendations is to replenish glycogen stores. Glycogen is considered essential to optimal resistance training performance, with as much as 80% of ATP production during such training derived from glycolysis [6]. MacDougall et al. [7] demonstrated that a single set of elbow flexion at 80% of 1 repetition maximum (RM) performed to muscular failure caused a 12% reduction in mixed-muscle glycogen concentration, while three sets at this intensity resulted in a 24% decrease. Similarly, Robergs et al. [8] reported that 3 sets of 12 RM performed to muscular failure resulted in a 26.1% reduction of glycogen stores in the vastus lateralis while six sets at this intensity led to a 38% decrease, primarily resulting from glycogen depletion in type II fibers compared to type I fibers. It therefore stands to reason that typical high volume bodybuilding-style workouts involving multiple exercises and sets for the same muscle group would deplete the majority of local glycogen stores.

Ivy J, Portman R: Nutrient Timing: The Future of Sports Nutrition. 2004, North Bergen, NJ: Basic Health Publications

That is obviously talking about bodybuilding, but below is a sample from a research paper that discusses the benefits of a vegan diet for endurance athletes, and one of the downsides being that nutrient deficiency can pose to be a problem. I think it’s worth putting one of main chunks of the paper so be prepared for the long read…

Studies have shown that the beneficial effects of vegetarian diets in alleviating oxidative stress and regulating the anti-inflammatory response are based on their enormous non-nutrient content called phytochemicals [4,76]. Polyphenols containing flavonoids, phenolic acids, lignans, and stilbenes are the most diverse non-nutrient group of phytochemicals that are produced as secondary metabolites throughout plants and have a broad spectrum of effects on metabolic health [77]. Polyphenol research of the athletic population has often been conducted using various fruits and vegetables, mainly berries [78], including blueberries [79,80,81,82], black currant [83], Montgomery cherry [84,85], and pomegranate [86]. Acute polyphenol intake or supplementation of ~300 mg 1–2 h before training or >1000 mg of polyphenol supplementation (equivalent to 450 g blueberries, 120 g blackcurrants or 300 g Montmorency cherries) 3 to more days (1–6 weeks) before and immediately after training is recommended as a countermeasure to improve antioxidant and anti-inflammatory response mechanisms [87]. However, only two studies examined the effect of vegetarian diets on exercise-induced oxidative stress in endurance athletes by comparing them with omnivorous diets, revealing contradictory results [53,55]. An incremental exercise test was applied in both studies. Nebl et al. [53] showed that nitric oxide levels, also known as an important biomarker for inflammation, endothelial and vascular function, did not alter between groups. In addition, exercise-induced malondialdehyde (MDA) concentration, an end product of lipid-peroxidation that is commonly measured to detect oxidative stress, significantly increased in vegan athletes in both studies, and in LOV athletes compared to omnivorous athletes [53]. Further, Potthast et al. [55] found a negative interaction between MDA, and sirtuin activities and antioxidant intakes such as ascorbate and tocopherol. These studies showed opposite results, against expectations, i.e., vegetarian diets increased the antioxidant response while suppressing the oxidant response. One explanation might be that the MDA test may not provide accurate measurement in biological samples due to its high reactivity and cross-reactions with other biochemicals available in the body despite its widely usage as an oxidative stress biomarker [88]. Therefore, studies with a greater sample size and including other oxidant parameters are needed to clarify these findings.

In addition to polyphenols, Interleukin 6 (IL-6) has often been identified as an inflammatory biomarker associated with fatigue, skeletal muscle inflammation, and differentiation of immune response, as well as an inducer of the metabolic acute phase response to infection [4,89,90,91]. It has been suggested that endurance athletes consuming vegetarian diets may have lower IL-6 concentrations and a lower IL-6 increase in response to endurance performance [4]. These data are explained by the positive interaction between muscle glycogen and IL-6 concentration, based on the information that higher muscle glycogen stores cause lower IL-6 elevations [92]. The higher CHO content of vegetarian diets may increase muscle glycogen stores, resulting in a down-regulated IL-6 response to endurance performance [4]. However, there are no data comparing the vegetarian and omnivorous diets for IL-6 concentration in endurance athletes.

One further point is the possible roles of vegetarian diets in URTI [73]. It is well known that endurance athletes are at greater risk for URTI due to prolonged and excessive training or races that cause immunosuppression and immune deficiency [93]. The possible link between URTI and a vegetarian diet may be explained with an emphasis on its polyphenolic content [94]. Polyphenol supplementation is also preferred in endurance athletes because of its debilitating role in URTI, one of the risk factors that often arise after immunosuppressive endurance exercise. A meta-analysis by Somerville et al. [73] reported that flavonoid supplementation reduced the incidence of URTI by 33% compared to a control group. Researchers also examined all factors that may cause a bias between studies, indicating that the risks for sequence generation, allocation concealment, and reporting bias are unclear in the included studies in the systematic review [73]. On the other hand, in a crossover design, Richter et al. [54] compared the influence of a 6 week LOV diet versus a meat-rich Western diet on in vitro measurements of immunologic parameters in male endurance athletes. The findings reported that no change was detected in CD3+ (pan T-cells), CD8+ (mainly T suppressor cells), CD4+ (mainly T helper cells), CD16+ (natural killer cells), CD14+ (monocytes) after the two diet trials and none of the immunological parameters differed from each other after the two diets. Studies have commonly focused more on diet content rather than diet pattern whether vegetarian or omnivorous. Therefore, the potential immunological benefits of vegetarian diets need to be investigated further.

A review investigating the effect of vegetarian diets on cardiovascular health in endurance athletes highlighted that vegetarian diets can provide better cardiovascular protection by reducing plasma lipid levels, exercise-induced oxidative stress, inflammation and blood pressure, and improving endothelial function and arterial flexibility [71]. One cross-sectional study confirmed the information by investigating the difference in heart morphology and function according to the vegan and omnivorous diets in amateur runners [59]. The results showed that vegans had better systolic function, determined by longitudinal strain (vegan:−20.5% vs. omnivore:−19.6%), and diastolic function in vegans, determined by higher E-wave velocities (87 cm/s vs. 78 cm/s), compared to omnivorous athletes [59]. Therefore, we can confirm that vegetarian diets may have a beneficial impact on cardiovascular function; however, we still need further investigation on endurance athletes.

Devrim-Lanpir A, Hill L, Knechtle B. Efficacy of Popular Diets Applied by Endurance Athletes on Sports Performance: Beneficial or Detrimental? A Narrative Review. Nutrients. 2021 Feb 2;13(2):491. doi: 10.3390/nu13020491. PMID: 33540813; PMCID: PMC7912997.

Polyphenols 

Although polyphenols and their relationship with endurance still seems to be unambiguous, it’s worth noting that their may be some benefits to consuming polyphenol rich foods to promote anti inflammation in the body. I made a youtube video talking about Polyphenols here:

Overall, the available literature seems to suggest that nutraceutical bioactive compounds as polyphenols, known for their effects on degenerative and chronic diseases, can also provide protection against exercise-induced muscle damage and oxidative stress thanks to their antioxidant and anti-inflammatory properties. However the possibility to improve the exercise performances remains unclear. 

Malaguti M, Angeloni C, Hrelia S. Polyphenols in exercise performance and prevention of exercise-induced muscle damage. Oxid Med Cell Longev. 2013;2013:825928. doi: 10.1155/2013/825928. Epub 2013 Jul 24. PMID: 23983900; PMCID: PMC3742027.

Timing Meals for Strength and Endurance Athletes

Pre training meal 1 (2.5-4 hrs before)

Nutrition of Food:

• Low in fiber and fat

• 20-30 grams of protein

• 1-4 grams/kg: about 200-300 grams of carbs for a 56-60kg for example

Example: 

• 4 oz chicken breast (25 grams protein)

• 1 serving oatmeal (4 grams fiber, 27 grams carbs)

• 200 grams of potato (about 200 grams carbs)

• .5-1 liter of water

Pre exercise meal 2 (30 minutes before)

Nutrition of Food:

• Low in fiber and fat, 

• High in fast acting carbohydrates

• No protein

• 1-4 grams/kg

Example: 

• 1 serving honey nut cheerios or  

• 1 cup pineapple (too much water though) or

• Fruit gummies, banana

Post exercise meal 3 (2+ hrs post)

Nutrition of Food:

• Quality protein and carbs

• Carbs of 1-1.5 grams/kg for every hour after training for 2-4 hours 

Example: 

• 1 cup of rice (30 grams carbs) 1 hour after 

• 1 cup of melon (50 grams carbs) 2 hour after etc. 

• Continue hydrating 

I purposefully put these two the same because relatively speaking their may not be much of a difference between the two in timing, and their are a lot of factors that can influence the digestion of the foods, the kinds of foods you eat etc. In other words we can adapt to lower glycogen or higher glycogen stores. If you are training for something and can exercise on a full stomach fine, it is probably safe to assume that that method works for you; there is still a lot of individualized variables to this:

The question is thus raised of whether athletes, for example, those who are involved in prolonged sub maximal exercise, should always consume a high carbohydrate diet [39]. Moreover, it has been proposed that athletes can adapt to lower muscle glycogen stores (Wardaneer et al., 2017). Full article here

Conclusion

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Be well.