Is coffee good for our body or is it bad for our health?
The latest research shows that coffee doesn’t have any serious negative health effects, but it can actually carry some surprising benefits! (1)
Did you know that roasted coffee is a complex mixture of more than 1000 bioactive compounds and that some of those molecules may help you lose weight, protect your liver as well as lower the risk of Type 2 diabetes and Cardiovascular diseases (CvD)?
Stay with me while we investigate the health benefits of coffee on the human body!
Does coffee make you live longer? How does it affect the brain? Check out our previous article on the benefits of coffee!
Caffeine can help you lose weight
First off, let’s be clear on one point:
while black coffee is quite low on calories, a 24-ounce Starbucks mocha Frappuccino with whipped cream is not going to encourage any slimming down. It contains about 500 calories: that’s a fourth of your daily calorie intake! (1)
So do check how much milk or cream you’re adding to your coffee. You might be consuming more calories that you think.
And now… let’s get to the juicy stuff.
How does coffee promote weight loss?
There are three ways in which caffeine helps you lose weight: through thermogenesis and by stimulating fat oxidation.
These terms might sound haughty, but they enclose pretty useful information. Let me explain a bit more.
Caffeine boosts your metabolism
First of all, caffeine boosts your metabolism by increasing thermogenesis— that is, a metabolic process during which your body burns calories producing heat. You know when you exercise and you start feeling warm and then warmer until you’re all red and sweaty? That’s thermogenesis for you.
So, one study found that a single cup of coffee (100 mg of caffeine) could increase your resting metabolic rate by 3-4%. That means you’re burning calories even if you’re doing nothing at all!
Then, scientists gave participants more cups of coffee and, after 12 hours, they observed that they had consumed more energy than usual: an increase of 150 kcal in the lean volunteers and 79 kcal in the postobese subjects. (2)
Not too bad burning calories simply by drinking coffee!
Caffeine helps burn fats
Secondly, it stimulates fat oxidation: that’s when the bigger fat molecules in your body are broken down in smaller ones.
And as usual, some scientists got together, gave some caffeine to a group of women and, next day, lipid oxidation had increased by 29 and 10% in lean and obese women, respectively. (3)
high caffeine consumers reduced weight, fat mass, and waist circumference more than low caffeine consumers. (4)
However, weight loss is not the only health benefit of caffeine. It also makes you last longer… in sports!
Coffee enhances sports performance
Do you remember when we talked about caffeine causing fat oxidation? Well, the smaller fat molecules which come out of that process are a great source of available energy for the body.
When exercising, for example, it increases endurance (in athletes and, if you ever wondered, also in rats). (5) A study found that caffeine improved exercise performance by 12.3%. (6) This makes caffeine an ergogenic substance.
However, other scientists think caffeine’s ability to break down fat is not the only factor involved. In fact, they suggest that caffeine may also be fooling you into feeling less physically tired: it messes with your perceived exertion. (7)
What’s more, caffeine also produces an increase in adrenaline (epinephrine), the hormone that, by making the heart beat faster and muscles contract, provokes our “fight or flight” response which makes us ready for action or a good run. (8)
But there is more!
Coffee reduces the risk of Type 2 Diabetes
Diabetes is a chronic disease that occurs either when the pancreas does not produce enough insulin or when the body cannot effectively use the insulin it produces. Because insulin regulates blood sugar, hyperglycaemia (high blood sugar) is a common effect leading, over time, to serious damage to many organs in the body.
Sadly, in 2015, diabetes was the direct cause of 1.6 million deaths worldwide and Type 2 Diabetes is the most common form. (9)
Remarkably, studies have repeatedly shown that coffee consumption is directly related to a reduced risk of developing Type 2 Diabetes: in particular, for each extra cup up to six cups the risk lowered. (10)
Two particular components of coffee seem to be responsible: cafesol, which increases blood sugar intake in the cells, and caffein acid. Both also increased insulin secretion. (11)
However, as this was a study on rat cells and not human cells, there is a lot which needs to be confirmed with more studies.
Coffee has protective effects on the liver
Coffee contains molecules such as Chlorogenic acid, caffeine and diterpens (cafesol and kahweol), which have anti-inflammatory and antioxidant effects. Surprisingly, coffee is the most common source of antioxidants in the Western diet. (10)
These are likely responsible for the mechanism behind the beneficial associations between coffee consumption and liver diseases such as hepatitis, fibrosis and cirrhosis. In addition, caffeine could have direct antifibrotic effects by preventing hepatic stellate cell adhesion and activation. (12)
Put it this way:
usually, the liver does a great job at detoxing the body. But when it’s under too much strain, it can get damaged. So, it tries to repair itself and as a consequence develops scar tissue (fibrosis). When this gets worse it develops into a cirrhosis.
What it all comes down to is that coffee can help reduce the damage to the liver and prevent scarring. And, impressively, people who drink even one cup of coffee against people who drink none have a 29% lower risk of non-alcoholic fatty liver disease, a 27% lower risk for liver fibrosis and a 39% lower risk for liver cirrhosis. (12)
Coffee has beneficial effects on Cardiovascular diseases
we’ve all felt our heart flurry at least once after a cup of coffee and it wasn’t because of that attractive colleague by the coffee cart. We might have had an irregular blood pressure that day or maybe we hadn’t been drinking coffee in a while.
If we’re not used to drinking coffee, when we do, it gives us a significant increase in blood pressure which declines after our body habituates itself to the drink, in about a week. Even after a couple of weeks we still see our pressure being a bit higher than usual. (1)
Does it mean that coffee is bad for your heart? Not necessarily.
Oddly enough, many long-term studies have found that moderate coffee consumption (around 3 cups a day) was associated with a decreased risk of Cardiovascular Diseases (CVD) and mortality. If you drink more or less than 3 cups a day there is no improved benefits, but also no more risks. (13)
And the benefits are impressive:
compared with non-drinkers, risks were reduced by 19% for mortality from Cardiovascular Disease, 16% for mortality from coronary heart disease, and 30% for mortality from stroke, at this level of intake. (13)
Coffee and cholesterol
By contrast, there seems to be consistent evidence for small increases in our total cholesterol levels, LDL cholesterol (that’s the “bad” one) and triglyceride. And the culprit might be diterpenes.
Interestingly, the brewing method influences the amount of diterpenes in our drink: filtered coffee gets rid of most of them, while Turkish and French coffees have high levels, and espresso is sort of in the middle. But if we abstain from coffee for a while, lipid levels usually go back to normal. (12)
A word of caution:
There are some people who are more sensitive to coffee, who are not able to metabolise it as fast as others. It’s not their fault: it’s in their genes!
More accurately it’s caused by a specific manifestation of one of their genes: the *1F allele associated to Cytochrome P450 1A2 (CYP1A2), which is the main responsible enzyme for the metabolism of caffeine.
If people have this slow allele, it’s probably a good idea to abstain from coffee or risk hypertension. (14)
In a nutshell:
Coffee has many surprising positive effects on the body.
On the one hand it helps you lose weight by boosting your metabolism and breaking down fat cells. Beyond that it enhances sports performance because it gives you energy and makes you feel less tired.
On the other hand, with its antioxidant and anti-inflammatory effects it protects your liver, while also lowering your risk of Type 2 Diabetes and Cardiovascular diseases.
You probably want to stick to black coffee most of the time and leave that whipped cream pick-me-up for a rainy day.
Warning: The contents of this website are for educational purposes and are not intended to offer personal medical advice. You should seek the advice of your physician or other qualified health provider with any questions you may have regarding a medical condition. Never disregard professional medical advice or delay in seeking it because of something you have read on this website.
(1) Harvard T.H. Chan School of Public Health, Ask the Expert: Rob van Dam on coffee and health. 2015
(2) Normal caffeine consumption: influence on thermogenesis and daily energy expenditure in lean and postobese human volunteers. Am J Clin Nutr, 1989
(3) Effects of caffeine on energy metabolism, heart rate, and methylxanthine metabolism in lean and obese women. Am J Physiol, 1995
(4) Body weight loss and weight maintenance in relation to habitual caffeine intake and green tea supplementation. Obes Res, 2005.(5) Caffeine as a lipolytic food component increases endurance performance in rats and athletes. J Nutr Sci Vitaminol (Tokyo), 2001.
(6) Effects of caffeine ingestion on exercise testing: a meta-analysis. Int J Sport Nutr Exerc Metab, 2004.
(7)Effects of caffeine ingestion on rating of perceived exertion during and after exercise: a meta‐analysis. Scandinavian journal of medicine and science in sports, 2005.
(8) Morning Coffee Boosts Blood Pressure, Stress Hormones All Day. Science Daily, 1999.
(9) Diabetes fact sheet. WHO, 2017.
(10) Coffee consumption and health: umbrella review of meta-analyses of multiple health outcomes. BMJ, 2017.
(11) Cafestol, a Bioactive Substance in Coffee, Stimulates Insulin Secretion and Increases Glucose Uptake in Muscle Cells: Studies in Vitro. J. Nat. Prod., 2015.
(12) Four or more cups of coffee a day may keep prostate cancer recurrence and progression away. FredHutch, 2013.
(13) Tea and coffee consumption and cardiovascular morbidity and mortality. Arterioscler Thromb Vasc Biol. 2010.
(14) CYP1A2 genotype modifies the association between coffee intake and the risk of hypertension. J. Hypertens, 2009.