Is coffee good or bad for your health? Yes.

I’m often asked if coffee is good or bad for us….and the answer is yes.

First, how much can we consume in a day?

NHS guidelines in the UK advise healthy adults consume no more than 400 mg caffeine per day.

To put this in perspective, a single shot of espresso has somewhere between 45 and 75mg of caffeine - the average is around 63 mg.

So aiming for no more than 4 cups of coffee daily is a good rule of thumb.

For those who are pregnant, it's recommended to limit caffeine to no more than 200 mg per day (about two cups) or up to 300 mg per day while breastfeeding.

And don’t forget that decaffeinated coffee does still contain caffeine, just nowhere near as much as a 'normal' cup of coffee. A single shot of decaf espresso will contain around 10 mg of caffeine.

So what happens to your body when you drink caffeine?

You feel alert and energised.

Caffeine’s claim to fame is all related to the biochemical processes that occur soon after consumption.

For one, caffeine blunts the effect of adenosine, a chemical in the brain responsible for making you feel tired. As a result, you may feel less groggy and more alert, especially if you didn’t sleep well the night before.

Caffeine also triggers the release of the stress hormone epinephrine (a.k.a. adrenaline), which activates the body's "fight or flight" response.

Your heart rate increases, your blood supply to muscles increases, and glucose is released into the bloodstream, all of which can make us feel a sudden boost in energy.

Coffee can also improve your mood, because when we consume caffeine, our brain receptors become more sensitive to dopamine, the "happy hormone".

Keep in mind though, that this buzz is short-lived. The only way to actually "energize" the body is by consuming macronutrients (carbs, proteins and fats) from food. Take this as a reminder to eat breakfast along with your caffeinated beverage of choice.

You’ll find yourself in the bathroom, sooner or later.

Caffeine is a diuretic, meaning it tells the kidneys to release water and produce urine.

But contrary to popular belief, caffeine won’t cause dehydration. In fact, caffeinated beverages in moderate amounts count toward your daily fluid intake.

And while it's often assumed that the caffeine in coffee also has a laxative effect, new research suggests it's coffee's influence on our microbiome, and not necessarily the caffeine itself that’s the trigger.

It can also improve your workout.

Caffeine is considered a legal ergogenic aid (a.k.a. performance enhancing substance) at certain doses.

And it appears to enhance performance of aerobic (like running) and anaerobic (like strength training) activities, for both professional athletes and casual exercisers alike.

Benefits are seen at doses of 3 to 6 mg/kg body weight (about 3 shots of espresso for a 10-stone adult), consumed about an hour before a workout.

And while we lack sufficient evidence to say that caffeine increases metabolism enough to promote weight loss, a recent study found that drinking a cup of strong coffee 30 minutes before an aerobic workout may increase fat burning.

But it’s not all positives.

Whilst it might feel like consuming coffee has some magically positive effects, it’s no miracle drug and it might be harmful if you drink too much.

You could lose precious sleep.

One of the more costly side effects of too much caffeine is its impact on a good night's rest.

Consuming caffeine in high amounts or too close to bedtime can impact overall sleep quality, keep us from falling asleep and reducing the number of hours slept.

While some may do just fine with a mid-afternoon pick-me-up, it's generally advised to cut off the caffeine at least 6 hours before bedtime, as this is about the time it takes for our bodies to metabolise it.

For those with sleep problems, like insomnia, I’d consider reducing overall caffeine intake or cut it out by noon.

You can become mildly dependent on it.

The rise in dopamine after consuming caffeine is also the reason we might feel "addicted" to coffee.

If you've ever been hit with a mid-morning headache or feelings of irritability after missing your morning brew, you know what I’m talking about.

Feeling addicted to caffeine is not recognised as a true addiction, but because of the mild withdrawal symptoms that can be experienced in its absence it can sometimes be considered a dependency.

If you do decide to quit caffeine, any withdrawal symptoms, like headaches and fatigue, shouldn't last more than a few days.

It can mess with your mental health.

That temporary mood boost that occurs when caffeine is consumed in moderate amounts can also lead to feelings of agitation as consumption increases.

For some, that can make anxiety, panic and other mood and mental health disorders worse.

So in summary

Coffee can be both good or bad for us. Like with many foods and drinks we all enjoy, moderation is key with caffeine, too.