For millions of us, starting a day without coffee is not surprising.
But experts warn that it is better to prevent caffeine hits after breakfast because drinking coffee regularly may increase your risk of developing type 2 diabetes in the long run.
Researchers at the University of Bath asked 29 volunteers to drink a strong black coffee about an hour after waking up to understand how it would affect their blood sugar after breakfast.
After that a sugar-rich drink – calorie content with cereal or toast with jam – when they went without coffee their blood sugar was almost 50 percent higher. The caffeine present in the drink is thought to prevent muscles from absorbing sugars.
This may not be an immediate problem, but repeated increased blood sugar can lead to diabetes and heart disease, the British Journal of Nutrition said.
The study’s senior author, Professor James Bates, said: ‘About half of us will wake up in the morning and drink coffee, before doing anything – instinctively the more tired we feel, the stronger the coffee.
‘I love coffee a lot, and I’m not necessarily asking people to go without it, because it has some benefits.
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‘Maybe people don’t have caffeine in their system after a while, or until they wait to work, when they eat a snack containing carbohydrates and sugar.’
It is believed that about 40 per cent of people in the UK drink coffee as soon as they wake up in the morning.
Researchers wanted to see its effects in sleep-deprived people, so the study participants asked to set an alarm to go away every hour during the night.
When they awoke, the researchers gave them simple yoga-like questions every 30 seconds that they had to answer, to ensure that they did not sleep.
The study looked at people’s blood sugar and insulin levels on three occasions – after full sleep at home with no coffee at night, after sleeping with no coffee in their bed, and after a broken sleep and coffee.
It was 300mg strong black coffee – equivalent to two standard cups.
After breakfast participants’ blood sugar was tested, which was 30 minutes after coffee.
The study, published in the British Journal of Nutrition, found no effect on coffee or sleep deprivation on insulin levels.
However, strong black coffee intake before breakfast significantly increases blood glucose response, blood tests showed more than two hours.
Professor Bates said: ‘This study is important and has far-reaching health implications because until now we had limited knowledge of what coffee is doing for our bodies, especially for our metabolism and blood sugar control.’