Bars, Gel, or Sports Drink?

It's 9:00 PM the night before a competition or a long-distance session, and you're eyeing all the gear laid out on the bed. An important question always pops up… How am I going to fit it all in? Let me break down the science behind what's best – sports drinks, bars, or gels. Is there even a best choice? Maybe it's just about practical differences?

Researchers have, of course, examined this area and have answers to the question. In 2010, a research team was assembled to investigate how sports drinks, gels, and bars are absorbed and used as energy in the body, and whether there is any difference in absorption rate and gut issues between solid and liquid foods.

The quick answer is — water. Jokingly, we can describe it as a gel being a sports drink mixed with very little water, while a bar is a gel that has been left in the sun for a few hours and dried out. Breaking down the products into their macronutrients, it is usually some form of carbohydrate source (oats, glucose syrup, fructose, dextrose), possibly a bit of amino acids/protein, and lastly salts/minerals and water. In bars, we often find a bit of oil to give the bar its texture. Enough that there are significant differences between different types of gels when it comes to digestibility and absorption rate.

The advantage of gels and bars is that they are concentrated energy sources, meaning their weight is lower (you're not carrying any water). The benefit of sports drinks is that they also provide water and salts that you lose during training and competition. From a performance perspective, sports drinks are the smartest choice, provided you have space for the fluid on your bike.

If both of these energy sources are compositionally optimized, the difference in absorption and oxidation is very slight. The gel is a bit more viscous, and the bars have a firmer structure, slightly slowing gastric emptying—partly due to the gel fibers like guar gum in the gel and the increased fiber and fat content in the bars. With recent research, we now understand that gastric emptying isn't the system's bottleneck, contrary to beliefs from 10–15 years ago. Older studies focused more on molecular weight and stomach transit speed to optimize these steps. Today, we know that factors such as molecular weight are quite irrelevant; a higher molecular weight might even be detrimental to us.

Thus, how quickly something passes through the stomach doesn't seem to be the main limitation—the true constraint occurs further down in the gut when the energy is absorbed into the blood. It has been shown that the ratio should be 2:1 or 1:0.8 between glucose and fructose to deliver the maximum energy while being gentle on the stomach. Many gels and even bars are formulated in this way, which often means they are well-tolerated by the body. But what did the research team conclude?

Without diving too deep into the science, researchers found no difference in absorption or energy extraction between sports drinks and gels, provided you drink water with your gels. Whether you keep water in your bottle and get your energy from gels, or mix sports drink directly into your bottle, makes little difference. Practical aspects are what really determine the choice here.

It's also worth noting that the group who only drank water during cycling managed well; they burned the same amount of energy in all trials but relied more on fatty acids for fuel when they only had water. They also felt the effort was somewhat harder, which isn’t surprising — cycling for 3 hours with just water is tougher than with energy, even at lower intensities. However, it's known that most who use gels consume less liquid than those who drink their energy as sports drinks. Here, external temperature, distance, time, and access to fluids during the race will determine the setup that suits you best.

Here, the research team had nearly the same setup. There were 8 well-trained males with a VO2max of 69 ml/kg/min, showing slightly better oxygen uptake than the participants in the previous study. Otherwise, the studies were nearly identical. The participants consumed 1.6 g of carbohydrates per minute from either bars or sports drinks. With the bars, they also consumed slightly more fat and fiber compared to the sports drink.

Just like in study 1, the perceived exertion was similar between bars and sports drinks but slightly higher when they only had water. However, the perceived satiety was higher when they ate bars compared to both sports drinks and gels—which isn't very surprising, as the bars are more filling. All results also confirm a previous study that investigated the same topic.

Remember that all energy sources matter. You only have one gut and one absorption system. While it can be trained, it's still not invincible. Whether you're eating bars, gels, or drinking sports drinks, it ultimately breaks down into glucose and fructose, which are absorbed and used as fuel for your engine. If you're consuming 1.8 g of carbohydrates per minute, which is just over 100–110 g per hour, you probably can't eat a bar at the same time — the cup will overflow, and gut issues will occur. You shouldn't ingest more than your body can absorb, and the limit is around 100 g/hour if the energy source has the correct carbohydrate composition (glucose:fructose in a 2:1 ratio or possibly 1:0.8 if you're an experienced carbohydrate consumer).

• If you're hungry — have a bar.
• If you're thirsty — sip on a sports drink.
• If it's more convenient to carry gel (such as when you're running) — use gel.