DR MICHAEL MOSLEY: Why you should AVOID coffee first thing… and eat last night's pasta for lunch! Lessons I have learned from wearing a trendy blood sugar monitor
- Read more: DR MICHAEL MOSLEY: Why you stop losing weight when on a diet
I love self-testing: I regularly test my blood pressure and cholesterol. And, as many of you will know by now, I was once diagnosed with type 2 diabetes, and while I reversed it, I also still check my blood sugar levels.
It’s something more of us should do — millions of Brits have an abnormally high blood sugar level but many are blissfully unaware of the damage this is doing to their arteries and nerves.
An estimated seven million people in the UK have prediabetes (i.e. raised blood sugar levels that can be a precursor to full-blown type 2 diabetes) — but a good proportion won’t know it.
And even if you don’t go on to develop type 2 diabetes, simply having prediabetes increases your risk of premature death by more than 60 per cent.
You can check your blood sugar levels using a standard DIY fingerprick test (for around £20) from the High Street or online. These kits are reliable; if the result suggests you have a problem then do talk to your GP.
Many people with diabetes now use a continuous glucose monitor (CGM) — the coin-sized device, which sticks to your arm and has a tiny needle that measures your blood sugar levels: you then link it to your smartphone, and within an hour it will start giving readings, updated every 15 minutes. Theresa May, who has type 1 diabetes, wears one.
But while these devices are intended for people with diabetes, anyone can buy one (they cost around £60 and last for two weeks), and they’re increasingly being used by people — including TV presenter Davina McCall — who want to see what foods (and activities) push their blood sugar levels up.
The idea being the fewer the big glucose spikes, the better.
I decided to try this out myself, not least to put some popular social media ‘hacks’ to the test.
So two weeks ago I bought myself a type of CGM called Freestyle Libre. So what did I learn?
Well, first, that the device takes a while to settle down — for the initial couple of days it suggested my blood sugar levels were far higher than the readings from my fingerprick monitor (which is more reliable). If I hadn’t known this, I might have been very worried.
After that — and not surprisingly — I found that anything sweet or carb-heavy (such as cake or breakfast cereal) soon pumped my blood sugar very high, followed by a crash which left me hungry — and irritable. Sadly this was also true of one of my favourite treats, dark chocolate, which contains a fair amount of sugar, around 4g (one teaspoon) per square.
More tragically, I discovered that coffee — even black and without sugar — led to big blood sugar spikes, particularly consumed first thing in the morning.