Energy Gels & Performance Nutrition

by Liam Tharme

With 78 minutes on the clock and Brentford 3-1 up at home to Liverpool in late October, Keane Lewis-Potter was being readied to come on.

Assistant first-team coach Mehmet Ali gave him some last-minute tactical instructions, before Ted Munson, the Brentford nutritionist, handed Lewis-Potter an energy gel.

He passed that gel to left-back Kristoffer Ajer, with Brentford bracing to defend a Liverpool surge. Despite a Mohamed Salah goal on 89 minutes, Keith Andrews’ side held on for a statement win, dealing with a barrage of Liverpool crosses (15) and shots (11) in the second half.

The victory owed to well-executed tactics and, in no small part, to their in-game fuelling.

To be clear, this is not a new thing. Brentford have a partnership with Science in Sport (SiS), a leading manufacturer of sports-specific nutrition products, which dates back to their Championship days in 2019. Tottenham Hotspur and New York City FC also have partnerships with SiS from the early 2020s.

At the 2019 World Cup, the England women’s team made gels a key part of their second-half strategy. They dotted them around the pitch (in blacked-out sachets to avoid any issues around marketing) for players to grab during breaks of play.

Eagle-eyed fans will see players, at various points of all Premier League matches, consuming gels. Often there are electrolyte drinks as well, while grassroots players of the 2000s grew up with orange slices and Jaffa Cakes to refuel. Just last weekend, television viewers of the Crystal Palace versus Manchester United game were shown a number of items in Dean Henderson’s goal: a cap (to ward off the low winter sun), some water, some vaseline (which goalkeepers use on their gloves) and… an energy gel.

Gels are something that cyclists, marathoners and triathletes have been using for years. These are liquid (often quite gooey) sachets of a high-carbohydrate solution. Some contain caffeine.

Fat, while a rich energy source, is not used because the process (ketosis) is too slow at this level of intensity. “Whereas to use carbohydrates, we can do that pretty quickly. That’s the quickest (aerobic) way we can do it,” says Bell, who uses the analogy of comparing a microwave (carbs) to an oven (fat) for energy production.

He explains that to solve the problem of fatigue and glycogen depletion, fuelling needs to happen early.

“You get to half-time in an elite game, particularly with the style of football these days — the ridiculous pressing, you’re running, running, running — and loads of fast-twitch muscle fibres are going to be exhausted of their glycogen (these fibres have higher stores than slow twitch ones because they use greater amounts to produce higher energy for more forceful contractions).

“We know from tons of research, when you’ve got somebody who’s got their glycogen stores depleted, they’re not going to be able to run as fast, produce the same force, or kick a ball as well.

“So if we don’t consider in-game nutrition, you’re going to go out to the second half and not be able to do the same amount of intensity or to perform the same amount of sprints at the same level, because you have not obviously got the glycogen to do so.”

This is particularly important, Blesa points out, for players whose clubs are in multiple competitions, and will often be playing three matches in a seven-day period: “We know that it takes 72 hours to recover, when we use all the recovery strategies available to us properly. In many cases, players do not have enough time to recover, which increases the risk of chronic fatigue, poorer performance, and more frequent injuries.”

So why not just consume an electrolyte drink — such as a Lucozade or Gatorade — or sweets or candy mid-match?

“Their impact on performance is different. The gel is faster, easier to digest, safer, and more effective,” Blesa says. Gels are smaller, so players do not have to deal with the uncomfortable feeling of liquid sloshing around while running.

Bell, who has an analogy for everything, simplifies gels to using a powerbank while watching a movie on your phone during a flight: “When we have this energy gel at half-time, we’re not improving our glycogen stores. We’re still ‘watching the film’, we’re still playing football, we’re still running. But the battery is not being chewed into for those 15 minutes — it’s a way of preserving energy.”

This is because gels are “fast-acting”, Bell explains. “They pass through the gut very, very quickly. They go from the oesophagus into the stomach, small intestine, and then they get absorbed through that small intestine into the blood.”

That absorption happens through carrier proteins that Bell — time for another analogy — describes like taxis.

“Glucose can only go in a blue taxi. We can only use roughly 60g of glucose per hour. At that (limit), all the taxis are taken. You cannot physically get any more glucose through your intestines.

“But fructose, another type of sugar, that can use a red taxi (a different carrier protein), and you can take around 30g per hour of that. If we use fructose, we can add an additional 30g of carbohydrate, so, instead of 60g per hour, we can now get 90g — you’re able to absorb more.”

This is why gels, with a hyperfocus on their glucose and fructose ratios, have become such a key part of endurance events such as marathons. Professional cyclists have been experimenting with ingesting 120g-150g of carbs per hour, while triathlete Cameron Wurf reportedly used 200g per hour during the bike leg of an Ironman event earlier this year.

As a 90-minute intermittent sport, football performance is not as contingent on fuelling, but it certainly matters, Bell says.

“It’s going back to thinking, towards the end of the game, ‘What can we do to maximise our glycogen stores?’. When we do that (take a gel), you’re going to increase your blood glucose, and because you’re using that, there’s more available, you’re going to use less of your muscle glycogen. So it’s just preserving it.”

The key period this affects is late in games, where a disproportionate number of goals are scored (compared to earlier during matches) and results can flip.

“Your brain uses glucose,” Bell continues. “So if you’re completely rinsing your carbohydrate stores and, importantly here, liver glycogen, you’re actually taking away glucose from the brain. So then, as you get in the latter stages of a game, well, guess what? You’re not going to be as mentally sharp.

“People never talk about this — they just talk about the sprints and how much of an engine they’ve got for it — about how lethargic you can get, because your brain’s suffering because it hasn’t got the glucose that it had at the start of the game.”

He picks out examples of Liverpool’s late match-winning goals in the opening rounds of this season, and Manchester City back in their title-winning campaign of 2023-24, when they scored 41 goals from the 60th minute and beyond.

“They’re (Liverpool and City) pinging the ball around, exhausting the opposition and, in those last 10, 15 minutes, yes, opponents are physically depleted, but also cognitively, they’re fried. Small percentages really add up towards the end and they just can’t perform to the same level.”

Like any form of training, over time, the body can build a tolerance to gels, allowing players to take more on. For instance, in Arsenal’s 1-0 away win over Fulham in mid-October — during a run of five matches in 14 days — right-back Jurrien Timber took a gel on 30 minutes.

“It is quite important that you tailor it to you,” says Glenn Murray, a former Premier League footballer for Crystal Palace and Brighton & Hove Albion who played well into his thirties, after rising up through the English football pyramid in the 2000s. “You can get your in-game diet wrong and you can crash sometimes, which can be a problem, or it can give you stomach cramps.”

He had problems sometimes post-match after drinking too much cold fluid. “On occasions, I found having a warm sugary drink at half-time was more beneficial.”

Sports nutrition has come a long way. “It’s more advanced,” Bell says. Plenty of brands now offer bespoke gels for footballers, which tend to include moderate sodium levels (salt) and potassium to try to reduce muscle cramps.

With the potential for high heat and extreme conditions at the men’s World Cup next summer in the United States, Canada and Mexico, and the compounding effect of the heightened physical demands of the modern game within the current calendar, gels become even more important.

To have such a focus on pre- and in-game nutrition “was almost frowned upon maybe 10, 20 years ago,” Bell recalls. “‘Just go out and play. What are you worried about?’, people would say.”

Now professional clubs have in-house nutritionists, and refuelling has become another piece of the performance puzzle.