Does Caffeine Increase Stress and the Risk of Belly Fat?

In all its iterations, caffeine has become an integral part of daily life for people around the globe — not just for a morning coffee or black tea fix, but also in sodas, pre-workout mixes and chocolate. It’s even part of some breakfast cereals and protein bars.

The compound is so prevalent one study found that when pregnant women have high caffeine levels, their babies can show caffeine withdrawal symptoms similar to what adults see, such as irritability, tremors and fast heartbeat (these symptoms tend to resolve in a few days).

With the ability of caffeine to stay in your system for hours, though, what kind of effect is that having besides giving you a quick energy boost? There is evidence that, like newborns, overconsumption can exacerbate emotional issues like anxiety, make you physically jittery, and potentially affect the cardiovascular system. But less known is that other systems of your body can also be sensitive to its effects—one major shift, for example, could be in your hormones.

One of the biggest ways caffeine could throw your hormones out of balance comes with the way your body handles stress, according to Erin Kenney, RDN.

Caffeine as a compound stimulates the secretion of two specific hormones almost immediately: epinephrine and norepinephrine. These are very similar — which is why they are named like that — and they’re released by your adrenal gland. Kenney says these are your main fight-or-flight hormones that surge during stress.

As they’re released in your body, it causes slightly increased blood pressure, faster heart rate and more shallow breathing. Basically, your body is getting ready to face a threat, and that’s why it’s prepping you with that jolt of energy and changed mechanisms. Simultaneously, this reaction can also kick off secretion of another stress hormone, cortisol — the one associated with increased belly fat — and these effects can last for hours.

“At a low dose, this reaction would be short-term, and if you’re generally healthy and not already stressed, it’s not much of a concern,” says Kenney. “But the more you consume, the more these hormones are released, and if you’re already feeling stress, it could be a problem.”

Drinking too much coffee won’t give you adrenal fatigue, but it can make you feel burned out faster, she adds. That’s because when these hormones remain surging throughout the day, you never get a feeling of rest. Even when you’re trying to downshift, you’ll feel on high alert — cue the issues with sleeping, digestion, mood changes, skin issues and other signs of chronic stress.

As the stress hormones keep doing their “get ready” action, it creates a ripple effect on other hormone as well, particularly insulin, the hormone that regulates blood sugar. For those who are trying to control their weight or keep metabolism steady, this might be a problem.

In a small study of 12 volunteers, researchers looked at the effects of caffeine on insulin and found caffeine decreased insulin sensitivity — the measure of how well your body is using the hormone — by about 15%. While that’s not a huge change, that increase was seen with the equivalent of only one cup of coffee for women and two for men in the study.

Although that research was limited by its modest participant number, it’s not the only one to make the connection. Research from the American Diabetes Association found high coffee consumption for four weeks increased insulin concentration and decreased insulin sensitivity.

Other research has indicated caffeine could also play a role in making regulation more challenging for hormones like estrogen, as well as mood-enhancing hormones like serotonin and dopamine.

With the type of potential hormone regulation effects that might come with caffeine consumption, does that mean it’s healthier to toss your coffee pot and swear off black tea forever? For most people, it’s not necessary to give up caffeine altogether, Kenney believes. (You can breathe that sigh of relief now.)

But it is helpful to be more aware of how it might be affecting you, especially if you have hormone regulation challenges already. That means if your thyroid health is a concern, you’re dealing with stress or sleep has become a struggle, it could be a good step to cut back caffeine, or even stop altogether for a certain period of time to see if your issues improve.

Kenney emphasizes that one important step is to understand how much caffeine you’re actually consuming. The amount can vary widely according to beverage or food, but she says the general recommendation is to stay around 200–400mg per day. That’s about 3–4 cups of coffee. But don’t forget to add in other possible caffeine sources like chocolate, pre-workout drinks, sodas and protein bars.

“Like other foods and drinks, moderation is key,” she says. “Absolutely, your favorite coffee drink can still be part of your life, especially if you’re employing other strategies to stay balanced like eating a nutritious diet, getting regular activity and focusing on keeping your stress managed.”

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