Go on, pour another cup of coffee, because we've got a good reason that your morning espresso habit might be a good thing. In fact, we've got two good reasons.

Researchers in both the UK and Denmark have found that over an extended period of time, high levels of caffeine in the blood can help protect the body against obesity. Furthermore, caffeine in blood plasma might be linked to a reduced risk of joint disease—specifically, osteoarthritis. If these things seem unrelated, they are not: the decrease in the risk of osteoarthritis was at least partly due to lower body weight (since heavier individuals can experience exacerbated joint problems).

The study involved nearly 10,000 participants and found that those who were genetically predicted to have higher circulating levels of caffeine were at a lower risk of both obesity and osteoarthritis.

Remember, though, correlation does not equal causation! However, the researchers used a technique called Mendelian randomization, which allows us to infer that there is at least some kind of causative relationship between the factors.

So, while we cannot definitively say that drinking caffeine causes weight loss, the results of this study suggest that the relationship between caffeine and obesity is more than mere coincidence. Some theories: the participants with a higher caffeine and lower weight also may have lower chronic inflammation, better lipid profiles and altered protein and glycogen metabolism.

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Caffeine and body weight: what’s the connection?

This recent study isn't the first time that science has suggested that there might be a link between coffee intake and body weight. Indeed, there have been several other studies showing that these two things are connected in various ways—although it's often been the link between caffeine and lower weight that's been established and not the actual cause.

One review and meta-analysis of randomized controlled trials found that caffeine intake could promote a reduction in weight, BMI and body fat. Another study by the Harvard T.H. Chan School of Public Health monitored 126 overweight, non-insulin-sensitive participants over the course of 24 weeks. The researchers ultimately found that drinking four cups of coffee a day was linked to a reduction in body fat by about 4%.

That's not all. In yet another study, researchers found that an increase in unsweetened coffee (both caffeinated and decaffeinated) was inversely associated with weight gain. In other words, when coffee intake went up, weight went down. And, interestingly, caffeine might even act as a slight appetite suppressant, nudging you to put your fork down sooner.

How does caffeine impact your weight?

You know that your morning Starbucks run is responsible for the nice jolt of energy you get at the start of your day, but what does it have to do with your weight?

The answer may lie, at least in part, with your metabolic rate. Your resting metabolic rate, or your RMR, is the rate at which your body burns calories at rest. The higher this rate is, the more calories you burn at rest, and the easier it should be to lose weight (and the more calories you can eat without experiencing weight gain).

Meanwhile, coffee consumption may offer a boost to your metabolism. Research tells us that caffeine can increase your resting metabolic rate by between 3% and 11%, and possibly more.

So, caffeinated beverages (like your coffee) could basically speed up your metabolism so that you burn more calories even when you're just sitting around!

Does caffeine affect fat metabolism?

It's important to be aware: weight loss doesn't always mean fat loss. However, this does seem to be the case with caffeine. Science has indeed found that caffeinated coffee can increase your fat metabolism. In fact, in one analysis of 94 studies with 984 participants, caffeine consumption significantly increased fat metabolism—with the effect more noticeable when caffeine was consumed at rest, compared to during exercise. This was recorded regardless of the participants' various individual factors, like fitness level and sex.

What are the health benefits of caffeine?

There are other reasons why drinking coffee isn't such a bad idea, outside of weight loss. For starters, drinking coffee might put you at a reduced risk of suffering from irritable bowel syndrome (IBS). This could be because coffee has a positive impact on your gut microbiome and can also decrease inflammation (a prominent player in IBS).

Second, despite popular belief, coffee also provides heart health benefits. For instance, science has found making coffee part of your daily nutrition can put you at a lower risk of developing a heart condition, even if you're only having one cup a day.

Plus, coffee is packed with antioxidants, which offer a wide variety of anti-aging and anti-inflammatory health benefits.

What's more, coffee might also be beneficial for women's health in particular. It can decrease the risk of death from some of the most common causes for women, including coronary heart disease, stroke, kidney disease and diabetes. There might even be a connection between increased coffee consumption and a decreased risk of developing Parkinson's disease!

So, it's not solely about avoiding weight gain. Yes, coffee might be an excellent fat burning addition to your daily routine if weight loss is on your mind, but it can also be good for your overall health and even help you live longer.

How much caffeine should you have a day?

Is more coffee better, or does it fall under the heading of "too much of a good thing is a bad thing"? The answer is…it's a little more complicated than that.

First, what's the approximate maximum you should drink when it comes to caffeine? The U.S. Food and Drug Administration says that the average healthy adult can safely have up to 400 mg of caffeine a day. That comes out to roughly four or five cups of coffee.

However, everyone reacts to caffeine differently, so it's better to experiment with different amounts of caffeine to see how your body responds. Regular coffee mixed with decaf might be a better option if you're sensitive to caffeine. After all, the fat burning benefits aren't going to be worth it if caffeine gives you horrendous anxiety or has you running to the bathroom.

We also want to point out that not all coffee is the same. Black coffee is very different from a drink loaded with sugar, cream and artificial sweeteners. These are okay as a treat but won't do much to improve your overall wellness. In fact, you could most certainly gain weight, not lose it, if you make high-calorie caffeinated treats part of your daily routine!

Something else we want to touch on is energy drinks, which can pack a big punch when it comes to caffeine. Is this the same as drinking high-quality coffee? Not quite. In some cases, you might actually get more caffeine than you bargained for. They're also usually made with a ton of sweeteners and contain other ingredients that might not be desirable for a health-conscious person.

Which coffee is best for weight loss?

If your goal is weight loss and improving your overall health, aim for a high-quality brew. Understand where the beans come from and how they're prepared. Use this as one part of a healthy lifestyle that also includes a nutrient-dense diet and plenty of physical activity. Remember that caffeine shouldn't be treated as a bandage or a replacement for overall healthy habits.

Long story short, if you're looking for another tactic to help you manage your weight, a moderate amount of caffeine can help. A healthy and stable weight is important not just for your current wellness but for your longevity, too.

However, if you're not sure if this is the right approach for you—and especially if you feel like you've tried everything but just can't lose weight—it's always a smart idea to speak with your healthcare provider before making any further changes to your nutrition and overall lifestyle. They might recommend that you undergo a weight loss panel blood test, to provide more insight into why the scale isn't budging.

References

• Conger SA, et al. "Does Caffeine Increase Fat Metabolism? A Systematic Review and Meta-Analysis." Int J Sport Nutr Exerc Metab. December 2022. https://pubmed.ncbi.nlm.nih.gov/36495873
• Duloo AG, et al. "Normal caffeine consumption: influence on thermogenesis and daily energy expenditure in lean and postobese human volunteers." Am J Clin Nutr. January 1989. https://pubmed.ncbi.nlm.nih.gov/2912010/
• Henn M, et al. "Changes in Coffee Intake, Added Sugar and Long-Term Weight Gain - Results from Three Large Prospective US Cohort Studies." The American Journal of Clinical Nutrition. December 2023. https://www.sciencedirect.com/science/article/abs/pii/S0002916523661702
• Ng QX, et al. "The role of inflammation in irritable bowel syndrome (IBS)." J Inflamm Res. September 2018. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6159811/
• Ren X, Chen JF. "Caffeine and Parkinson's Disease: Multiple Benefits and Emerging Mechanisms." Front Neurosci. 2020. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7773776/
• Schubert MM, et al. "Caffeine, coffee, and appetite control: a review." Int J Food Sci Nutr. December 2017. https://pubmed.ncbi.nlm.nih.gov/28446037/
• Tabrizi R, et al. "The effects of caffeine intake on weight loss: a systematic review and dos-response meta-analysis of randomized controlled trials." Crit Rev Food Sci Nutr. 2019. https://pubmed.ncbi.nlm.nih.gov/30335479/
• Zagkos L, et al. "Genetic investigation into the broad health implications of caffeine: evidence from phenome-wide, proteome-wide and metabolome-wide Mendelian randomization." BMC Medicine. February 2024. https://bmcmedicine.biomedcentral.com/articles/10.1186/s12916-024-03298-y
• Zehiroglu C, Ozturk Sarikaya SB. "The importance of antioxidants and place in today's scientific and technological studies." J Food Sci Technol. November 2019. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6828919/
• "Four cups of coffee a day associated with modest loss of body fat." Harvard T.H. Chan School of Public Health. 2020. https://www.hsph.harvard.edu/news/hsph-in-the-news/four-cups-of-coffee-modest-loss-of-body-fat/
• "Spilling the Beans: How Much Caffeine is Too Much?" September 2023. https://www.fda.gov/consumers/consumer-updates/spilling-beans-how-much-caffeine-too-much
• "9 Reasons Why (the Right Amount of) Coffee Is Good for You." Johns Hopkins Medicine. https://www.hopkinsmedicine.org/health/wellness-and-prevention/9-reasons-why-the-right-amount-of-coffee-is-good-for-you

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The Life Extension Health News team delivers accurate information about vitamins, nutrition and aging. Our stories rely on multiple, authoritative sources and experts. We keep our content accurate and trustworthy, by submitting it to a medical reviewer.