Is There Such A Thing As Too Much Coffee?

Despite what most have believed their entire lives, coffee does not cause dehydration. Image via Thinkstock.

One cappuccino with breakfast. A flat white at lunch. An espresso for that 3pm crash…

It’s not uncommon to rely on a coffee hit (or three) to help punch through the day.

In fact, Western countries drink such large quantities that coffee provides the diet more antioxidants than both fruits and vegetables combined.

But just because some is good does not mean more is better. Coffee, unfortunately, is no exception.

MORE: Adding butter and oil to coffee - what bulletproof coffee can do for you

What’s your caffeine tolerance?
Caffeine is a stimulatory substance.

That means consuming large quantities in a short period has side-effects; typically undesirable effects related to digestion and brain function.

The extent of these side-effects, however, depends largely on your personal caffeine tolerance: frequent coffee drinkers have a far greater threshold than their anti-coffee colleagues, for example.

Consumption of caffeine past your personal threshold is known to cause tremors, anxiety, insomnia and even heart palpitations. Particularly if you have a medical condition such as anxiety or high blood pressure.

For these reasons it pays to go easy and listen to how your body reacts to caffeine.

Does coffee cause dehydration?
Despite what most have believed their entire lives, coffee does not cause dehydration. Even if you drink it during an intense workout.

Published in the Nutrition Bulletin journal, authors of a study reviewing eight previous caffeine-hydration trials concluded, “There is no evidence at present that low to moderate intakes of caffeine, even when consumed around extreme exercise, affect hydration in a negative way.”

Note that caffeine intake on its own - such as a supplement - can cause excess urination and fluid loss, particularly at high doses. However, consuming caffeine as part of a drink - such as a regular cup of coffee - maintains hydration. In other words, the amount of water you consume with your coffee is more than enough to replace any fluids lost at the urinal.

How much coffee is too much?
The caffeine content per coffee cup varies greatly.

Home-brewed and instant coffee contains roughly 50-80 mg per small cup. A large or grande can contain around 300 mg.
For the majority of healthy adults, 400 mg of caffeine – or four coffees per day on average – appears to be safe.

Again, this depends on your personal tolerance and any existing medical conditions. It’s also important to note that safe levels of consumption, including the health benefits, count for nothing if excessive sugar and other unnecessary calories are added.

That means skipping the fancy coffees typically found in take-away coffee shops - a very-vanilla latte is not particularly healthy, no matter which way you look at it.

MORE: Ten health facts you didn't know about caffeine

Joe Leech is a Sydney-based clinical and sports Dietitian. He shares research-driven evidence at Diet vs Disease