Doctor's Casebook: Why you shouldn’t regularly drink coffee before breakfast

About half of the adult population wake themselves up with a strong cup of coffee first thing on a morning.

Saturday, 10th April 2021, 4:45 pm
Drink coffee after breakfast, not before. Photo: Getty Images

While that may shrug off the sleepiness that follows a night when sleep is disturbed, it may not be doing your metabolism a lot of good if you do it regularly or on a daily basis.

Indeed, if your breakfast consists solely of a strong cup of coffee you may not be doing yourself any favours.

Scientists at the University of Bath recently published some research that looked at the effect of broken sleep and drinking a morning coffee on a number of different aspects of metabolism.

They found that while one night of poor or broken sleep has little effect on one’s metabolism, drinking coffee to wake yourself up can have a negative effect on blood sugar control.

In this small study involving 29 men and women, the researchers asked them to take part on three separate overnight experiments.

In one experiment they had a normal night’s sleep and were asked to take a sugary drink on waking in the morning.

In the second they were wakened every hour for five minutes.

Finally, in the third they were again roused, this time, every hour for five minutes, but first thing in the morning they were given a strong black coffee to drink half an hour before being given the sugary drink.

The sugary drink was the calorific equivalent of a normal breakfast.

They all had blood tests to measure their blood sugar and insulin levels.

They found that there was little effect on metabolism from the single night of broken sleep.

Significantly, they found that the strong coffee actually caused the blood sugar to be 50 per cent higher than when no coffee was taken.

This effect continued when blood was tested afterwards at two hour intervals.

They suggest that this arises because the caffeine in the coffee has the effect of preventing the muscles from absorbing the sugar.

This does not mean that one should avoid coffee all together, but it does suggest that you have to be careful if you do this on a daily basis, because pushing the blood sugar up like this could put one at risk of diabetes and of heart disease.

Quite simply, it may be better to consume your morning coffee following breakfast rather than before it as a means of waking yourself up.