You may have heard caffeine speeds up your metabolism, but does coffee help you lose weight? Caffeine is often added to supplements that claim they can help you drop pounds but is there any evidence to back these claims up?
When it comes to the connection between caffeine and weight loss, there are three common claims. These are that caffeine will help you burn fat by speeding up your metabolism, secondly, that it boosts your energy for exercise, and finally, that it suppresses your appetite. We talked to a nutritionist and looked at the research to discover if coffee does help you lose weight, how it really affects your metabolism, and the long-term effects of drinking coffee.
Before you chug a cup of strong coffee and jump on one of the best exercise machines to lose weight, we’ve got the bottom of whether coffee really does help you lose weight or not.
Can coffee help you lose weight? Nutritionists weigh in
Nutritionist Hannah Hope (opens in new tab) says it’s not as simple as a clear yes or no answer on whether coffee helps weight loss. There have been studies supporting the idea that drinking coffee stimulates weight loss, but not enough of them for a consensus in the scientific community.
A 2019 meta-analysis (opens in new tab) reviewed over 13 randomized controlled trials on the effects of caffeine and weight loss and concluded that caffeine intake might promote weight, BMI, and body fat reduction.
On the other hand, a 2017 study published in the Journal of Food Science (opens in new tab) showed that drinking a cup of caffeinated coffee interfered with participant's taste buds, particularly their interpretation of sweetness, which means that people may end up consuming sweeter and sweeter foods or drinks (and in turn more calories) because of this.
How does coffee affect your metabolism?
Research conducted in 2020 showed that people who drank four cups of caffeinated coffee per day saw a 4% decrease in body fat, according to a 24-week randomized placebo-controlled trial published in the American Journal of Clinical Nutrition (opens in new tab). The study’s authors suspect this is because drinking coffee raises a person’s metabolic rate, which means more calories burned.
Hope explains some of the science behind coffee's effect on metabolism “Coffee contains many biologically active substances that can affect metabolism, not just caffeine. For example, there is a small amount of theobromine which is also found in cocoa. Theobromine stimulates thermogenesis in the body, where the body produces heat and increases the number of calories that you burn.”
“Coffee also contains chlorogenic acid, a polyphenol found in coffee. This exerts a pivotal role on glucose and lipid metabolism regulation, and there’s mounting evidence that this can be beneficial in reducing the risk of type 2 diabetes. It can also be seen as having anti-obesity effects. Its acts as a lipase inhibitor, meaning it stops the absorption of fats. It also stimulates intestinal mobility aiding bowel movements.”
Hope points to a 2021 study (opens in new tab) expounding the benefits of coffee for its prevention and treatment of type diabetes 2 and obesity through its reduction of fat storage by suppressing fat cell functions and supporting the gut microbiota.
Hope continues, “Caffeine works in weight loss by also stimulating the nervous system. Coffee can increase your resting metabolic rate (RMR), the rate you burn calories at rest, a small study (opens in new tab) demonstrated a 4% increase in RMR, but much of the research around this is pretty old.”
What are the long-term effects of drinking coffee?
While caffeine can be part of a healthy lifestyle, too much of it is not good for you. The Food and Drug Administration (opens in new tab) (FDA) lists the symptoms of overconsumption as insomnia, jitters, anxiousness, fast heart rate, upset stomach, nausea, and headaches. In addition, the FDA estimates toxic effects, like seizures, can be observed with rapid consumption of around 1,200 milligrams of caffeine.
Coffee may also be a bad idea for migraine sufferers. A 2019 study published in the American Journal of Medicine (opens in new tab) showed that consuming three or more caffeinated drinks daily could trigger migraines. The study looked at 98 adults who suffer from episodic migraines and found that the higher risk was eliminated when caffeine consumption was limited to only one or two drinks a day.
Caffeine has some other side effects that may escalate over time with excessive long-term caffeine use. First of all, caffeine is a diuretic (opens in new tab) (which can lead to increased urination) that could lead to chronic dehydration if you don't consume enough fluids in addition to coffee.
Caffeine may interfere with calcium absorption, which can be bad for your bone if you aren't eating enough calcium in your usual diet. Also, consuming caffeine too close to bedtime can disturb your sleep, making you even more tired (and caffeine-dependent) the next day.
Is it safe to use coffee for weight loss?
The National Institutes of Health (opens in new tab) state that it is not harmful to most people to consume up to 400mg of caffeine a day. If you do eat or drink too much caffeine, it can cause health problems, such as:
- Restlessness and shakiness
- Fast heart rate
- Dependency, so you need to take more of it to get the same results
It’s also worth noting that some people are more sensitive to the effects of caffeine than others.
Hope says, “The studies show that drinking two to four cups of coffee a day can have some health benefits, but over this, it starts to be detrimental to your health. So, from a nutrition point of view, I wouldn’t recommend more than two a day and it’s better to have these before midday. From a weight loss point of view, include coffee if you desire but keep it in moderation and perhaps consider green tea!”
For more, find out what the coffee and lemon weight loss trend is all about, and whether there are any benefits.
Catherine is a freelance journalist writing across titles such as Verywell Health, Healthline, The Daily Telegraph, Refinery29, Elle, and Vogue. She specializes in content covering health, fitness, wellness, and culture.
A once reluctant runner, Catherine has competed in 30 running events in the past five years and looks forward to one day running the London Marathon.
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