In Triathletes, Marathoners & Co! Potato Purée Can Replace Conventional Carbohydrate Gels W/Out Performance Loss!

The gastrointestinal issues may have been a problem for a few of the testers, but some clever "natural workout nutrition" company is certainly going to eliminate this minor obstacle very soon... and who knows: maybe they make the product more potent by adding whey, resistant starches, bicarbonate, or other potentially performance-enhancing ingredients on the way.

It's 2019 and everyone has been infected by the "sugar is the devil" and "carbohydrates are not essential" viruses. Everyone? No, there's a small group of loyal sugar-guzzlers who keep Gatorade & Co in business (for a good reason, by the way, 'cause CHO supplements are the best-researched ergogenic for endurance athletes).

Now, a new study by scientists from the University of Illinois at Urbana-Champaign (Salvador 2019) shows that homebrew... ah, homecooked potato puree will have the same ergogenic effects in non-pro cyclists as the expensive CHO gels.

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Figure 1: Graphical illustration of sport-specific VO2Max (ml/gk/min) in athletes.

From the corresponding press-release, we learn that the authors' goal was "to expand and diversify race-fueling options for athletes and offset flavor fatigue." To this end, Andrew John Wilhelmsen and colleagues recruited 12 participants: hobby cyclists with quite impressive VO2Max scores of 60.7 ± 9.0 mL/kg/min. While this leaves room for differences in both less and even better-trained cyclists, the subjects probably represent the average CHO gel consumer - hobby-cyclist with few years of successful training under their buttcheeks; and people who hope to improve their speed and endurance by squirting CHO containing gels (usually a mix of glucose and fructose) into their mouths.

In 16(!) individual sessions the participants consumed either water alone, a commercially available carbohydrate gel or an equivalent amount of carbohydrates obtained from a potato purée while they performed a 2 h cycling challenge (60-85%VO2PEAK) followed by a time trial (TT, 6kJ/kg body mass) in a randomized crossover design that included a definite nutrition prescription for the 24 hours before each of the tests.

When the absence of differences is evidence of benefits

To gauge the gastrointestinal passage and individual physiological effects of the treatments, the researchers administered both treatments with U-[13C6]-labeled glucose. This allowed them to estimate the gastric emptying rate of which previous studies show that it is blunted by suboptimal carbohydrate supplementation (Sutehall 2018).

Based on the corresponding data and blood samples that were collected throughout the trials, the scientists determined that...

• 

  Table 1: Nutrient composition of treatment conditions.

  blood glucose concentrations were higher (P<0.001) in potato and gel conditions when compared to the water condition
• blood lactate concentrations were higher (P=0.001) after the TT completion in both CHO conditions when compared to the water condition
• TT performance was improved (P=0.032) in both potato (33.0 ± 4.5 min) and gel (33.0 ± 4.2 min) conditions when compared to the water condition (39.5 ± 7.9 min); 
• in that, no difference was observed in TT performance between CHO conditions (P=1.00), in other words: potato mash was equally effective but not better than the CHO gel (see data in Figure 2, as well)

All in all, the evidence does, therefore, support the scientists' conclusion that "potato and gel ingestion equally sustained blood glucose concentrations and TT performance" (Salvador 2019). There's one caveat though: gastrointestinal side effects.

Plain potato purée can easily replace your super-sweet CHO gels if you can stomach it!

Unfortunately, the scientists reported significantly higher rates of gastrointestinal bloating, pain and flatulence with potato purée versus CHO gel and/or water - an effect of which co-author Nicholas A. Burd said that it "may be a result of the larger volume of potatoes needed to match the glucose provided by the gels" (press-release).

Figure 2. For the important performance markers, time-trial and power output, the pureed potatoes are just as good as the CHO gels, they are not (yet?) better as some internet news outlets claimed (Salvador 2019)

The scientists did yet also point out that the average GI symptoms were lower than in previous studies, indicating that both (carbohydrate) conditions were well-tolerated by the majority of the study's cyclists and, as I should add, there's always room for innovation in the form of reformulating plain potato purées in ways that improve their digestibility (and augment its putative performance benefits).

Intra-workout BCAA supplements are marketed specifically to resistance trainees. If they do have anti-catabolic effects, though, those are - just like potential fatigue reducing effects - significantly more likely to occur in endurance trainees | learn more

Bottom line: CHO gels may still have the digestibility edge, but if you tolerate them, they're just as effective as specifically designed CHO gels for endurance athletes.

Overall, the study at hand must yet be considered a proof of concept; one that expands the range of intra-workout CHO supplement options with a non-innovative whole-food alternative, which is not better than CHO gels but as effective as the booming sugary ergogenics to diversify hobbyists and professionals race-fueling choices.

Future studies should now elucidate, whether mixing in more potato starch or specifically designed resistant starches can change the situation and make the "natural energy gel" not just equally but even more potent than the gluey top dogs among endurance athletes' intra-workout supplements.

Using those "advanced" products and/or a similar plain potato purée 'supplement' as the study at hand, future studies should also include real-world tests during marathons and/or triathlon competitions to complement the results from well-controlled but eventually not 100% realistic exercise tests as they were used in the study at hand. In the meantime, why don't you just try if it works for you? 'cause if there's one thing that exercise science has shown and yet forgotten to mention time and again: individuality is king! | Comment!

References:

• Salvador, AF. et al. "Potato ingestion is as effective as carbohydrate gels to support prolonged cycling performance." Journal of Applied Physiology (2019 | ahead of print).
• Sutehall, Shaun, et al. "Sports Drinks on the Edge of a New Era." Current sports medicine reports 17.4 (2018): 112-116.