If an energy drink is your early-morning lifeline, you know how quickly the juice can take you from dragging to dialed-in. That’s because it’s common to notice the effects of caffeine more intensely when you don’t have food in your stomach, says certified personal trainer and registered dietitian Charlotte Martin, M.S., R.D.N., C.P.T. “You’re basically getting a faster, less buffered hit of the stimulant.”
The speed of the surge can be useful—especially if you have things to do and people to see. But that burst also comes at a price.
In the short term, “that quick hit of caffeine is more likely to cause jitters, shakiness, nausea or GI distress, or a generalized ‘off’ feeling,” Martin explains. On top of that, downing energy drinks on an empty stomach can mess with your sleep-wake cycle and hormonal health.
Ahead, a closer look at the cons of cracking a can open on an empty stomach. Plus, expert-backed tips for adjusting your routine so you can keep the boost without the backlash.
- ABOUT OUR EXPERTS: Charlotte Martin, M.S., R.D.N., C.P.T., is a certified personal trainer and registered dietitian. Kathleen Benson, C.S.S.D., C.P.T., R.D.N., is a board-certified sports dietitian with VNutrition.
The Cost Of Downing Energy Drinks on an Empty Tank
The most common side effect of chugging an energy drink on an empty stomach? GI distress.
Energy drinks can prompt the stomach to ramp up gastric acid production, says board-certified sports dietitian Kathleen Benson, C.S.S.D., C.P.T., R.D.N., of VNutrition. Normally, food helps neutralize or buffer that acidity. Without it, those digestive juices can irritate the stomach lining, increasing the risk of reflux, nausea, and general stomach upset, she says.
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“Caffeine can also stimulate colonic motor activity,” says Martin. That’s a clinical way of saying it can get your bowels moving fast, leading to an urgency to “go” that can disrupt your morning routine. On top of that, many popular energy drinks are carbonated. For some people, carbonation on an empty stomach can lead to increased bloating, pressure, or discomfort, Benson adds.
The Cortisol Spike of Cracking A Can
Interesting fact: Downing an energy drink, thanks to its high caffeine content, can increase the production of cortisol. Colloquially, cortisol is known as the stress hormone because it helps the body regulate stress, says Martin. But this misunderstood hormone also regulates the sleep-wake cycle.
Normally, “cortisol levels naturally rise in the morning as part of the awakening response,” Martin explains. This surge helps you feel alert, energized, and ready to take on the day. The thing is, caffeine also increases cortisol output—especially when consumed first thing in the morning, she says.
There are two potential risks here: First, your body can start to rely on the energy drink as an external driver of alertness, suggests Benson. Over time, “that can make you dependent on caffeine for energy, rather than your body’s natural wake-up signals,” she says.
Second, “layering stimulants on top of the normal cortisol output can amplify that stress-hormone signal,” Martin explains. This can potentially contribute to feelings of anxiety, restlessness, or a wired-but-tired crash later on. For individuals who are chronically under-sleeping and relying on energy drinks to power through, this effect can be even more pronounced.
Other Hormones Can Be Impacted, Too
The endocrine effects of drinking an energy drink on an empty stomach don’t start and stop with cortisol. Caffeine can also increase the body’s output of adrenaline, which raises your heart rate and increases alertness, says Benson. Without food in the system, this surge can feel more intense, often showing up as jitteriness.
“It’s also possible to experience a temporary reduction in insulin sensitivity and slightly more blood sugar variability,” she says. Why? Caffeine and adrenaline signal to the liver to release stored glucose (sugar) into the bloodstream.
Almost immediately, you get an extra quick hit of energy. But without breakfast in your belly to stabilize things, a noticeable dip will follow, according to Benson. This can manifest as exhaustion, shakiness, or irritability. “This impact can be especially noticeable with higher doses of caffeine, or when the beverage includes additional stimulant sources like guarana,” she says.
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To be clear: “That does not mean one energy drink on an empty stomach is causing metabolic catastrophe,” says Martin. But caffeine—especially when consumed on an empty stomach—can put you on a spike-and-crash energy roller coaster. If repeated over time, that up-and-down pattern may make it harder to maintain steady energy throughout the day, ultimately making you dependent on additional energy drinks to perk back up.
The Ideal Way To Down Your Morning Energy Drink
Rest assured, you don’t have to quit the most flavorful part of your morning to ease these side effects.
How do you mitigate them, though? It’s simple. “Don’t pair a stimulant bomb with literally nothing,” says Martin. Even a small amount of food can help take the edge off the caffeine, making it less harsh on both your GI and endocrine system.
Ideally, your pre-energy-drink breakfast will include a combination of protein and carbs, along with some fat and fiber, Martin says. Think Greek yogurt and fruit, toast with eggs, a protein smoothie, or oatmeal with nuts and milk. “The protein helps with satiety, carbs give your body fuel, and the other nutrients support digestion and stabilize energy,” she explains.
Timing matters, too. Benson suggests waiting 60 to 90 minutes after waking to pop the top on your favorite energy bev. “This allows your natural cortisol rise to do its job first, so the caffeine works with your body, rather than stacking on top of it,” she shares.
If that’s not realistic, even waiting 30 minutes and grabbing a quick 100- to 200-calorie bite (like half a banana, a spoonful of almond butter, or part of a protein bar) is healthier for you than guzzling an energy drink as soon as your alarm goes off.