The Fitness Doctor: Drink Coffee After Breakfast, Not Before, For Better Metabolic Control
By Dr. Fredrick Peters
A new study looked at the combined effects of disrupted sleep and caffeine on our metabolism – with surprising results. A strong, black coffee to wake you up after a bad night’s sleep could impair control of blood sugar levels, according to a new study. Research from the Center for Nutrition, Exercise & Metabolism at the University of Bath (UK) looked at the effect of interrupted sleep and morning coffee across a range of different metabolic markers.
Writing in the British Journal of Nutrition, the scientists show that while one night of poor sleep has limited impact on our metabolism, drinking coffee to perk you up from a slumber can have a negative effect on blood glucose (sugar) control. Given the importance of keeping our blood sugar levels within a safe range to reduce the risk of conditions such as diabetes and heart disease, they say these results could have ‘far-reaching’ health implications especially considering the global popularity of coffee.
For their study, the physiologists at the University of Bath asked twenty-nine healthy men and women to undergo three different overnight experiments in a random order:
- In one, condition participants had a normal night’s sleep and were asked to consume a sugary drink on waking in the morning.
- On another occasion, participants experienced a disrupted night’s sleep (where the researchers woke them every hour for five minutes) and then upon waking were given the same sugary drink.
- On another, participants experienced the same sleep disruption (i.e., being woken throughout the night) but this time were first given a strong black coffee thirty minutes before consuming the sugary drink.
In each of these tests, blood samples from participants were taken following the glucose drink which in energy content (calories) mirrored what might typically be consumed for breakfast.
Their findings highlight that one night of disrupted sleep did not worsen participants’ blood glucose / insulin responses at breakfast, when compared to a normal night’s sleep. Past research suggests that losing many hours of sleep over one and/or multiple nights can have negative metabolic effects, so it is reassuring to learn that a single night of fragmented sleep (e.g., due to insomnia, noise disturbance or a new baby) does not have the same effect.
Strong Black Coffee
However, strong black coffee consumed before breakfast substantially increased the blood glucose response to breakfast by around 50%. Although population-level surveys indicate that coffee may be linked to good health, past research has previously demonstrated that caffeine has the potential to cause insulin resistance. This new study therefore reveals that the common remedy of drinking coffee after a bad night’s sleep may solve the problem of feeling sleepy but could create another by limiting your body’s ability to tolerate the sugar in your breakfast.
This study is important and has far-reaching health implications, as up until now, we have had limited knowledge about what this is doing to our bodies, for our metabolic and blood sugar control.
Put simply, our blood sugar control is impaired when the first thing our bodies encounter is coffee, especially after a night of disrupted sleep.