Intermittent fasting — why I do it and what it actually looks like day to day

Most people in the world have been told that breakfast is the most important meal of the day. And it is — if your name is Mr Kellogg and you're trying to sell cereal.

I started intermittent fasting for two reasons. First, I was overweight and wanted to lose weight. Second, and more importantly now, to help keep my blood sugar levels under control. Both reasons turned out to be well served by the same approach.

What actually happens when you stop eating

When you sleep, your body is already fasting. During those hours, it's steadily working through its glucose stores — the sugar it has available as immediate energy. After roughly eight hours without food, those stores are largely depleted. At that point your body has a choice — find more glucose, or switch to burning something else.

The something else is fat. Your body starts breaking down fat stores for energy, which is exactly what you want if you're trying to lose weight. The longer you can extend that fat-burning window after waking up, the more effective it becomes. And if you go long enough, the body may even begin producing ketones — an alternative fuel source that, as I've written about elsewhere, cancer cells largely cannot use.

The breakfast myth

The idea that breakfast is essential — that skipping it will slow your metabolism, make you hungrier later and harm your health — is one of the most successful pieces of food industry marketing ever produced. The cereal companies funded a lot of the research that supported it. That's not a conspiracy theory, it's documented history.

What the more recent and independent research suggests is rather different. For many people, skipping breakfast and extending the overnight fast has real metabolic benefits — better blood sugar control, improved insulin sensitivity, and more sustained fat burning through the morning.

And if you do feel you need breakfast, make it a savoury one. Eggs on wholemeal toast, for example. The protein and fibre prevent the blood sugar spike that a bowl of cereal or white toast with jam delivers almost instantly. Sugary cereals and refined carbohydrates first thing in the morning are genuinely one of the worst ways to start your body's day.

What my day actually looks like

I don't deny myself everything

I want to be clear about something — this isn't about being miserable or obsessive. I still enjoy things I like. Tangfastics. Fruit pastilles. If I fancy them, I have them. The key is that I eat them within my feeding window so my blood sugar has time to stabilise before the overnight fast begins.

I've also developed a fairly reliable early warning system. If I've had something too sugary too late in the evening, I'll know about it the next morning — I'll wake up hungry, which tells me my blood sugar spiked and crashed overnight rather than stabilising. The body is very good at giving you feedback once you start listening to it.

The eating window — roughly eight hours

The approach I follow is broadly what's known as 16:8 — sixteen hours of fasting, eight hours of eating. From around midday to around 6 or 7pm. It sounds restrictive but in practice it doesn't feel that way at all, because most of the fasting hours are spent asleep.

The benefits go beyond weight loss and blood sugar. Fasting periods are associated with a process called autophagy — essentially the body clearing out damaged cells and recycling them. There's growing research interest in the relationship between autophagy and cancer. I find that compelling, even if the science is still developing.

The weight loss side of things

I came into this over 105kg. I'm now around 90kg — and I haven't eaten less, I've just eaten differently and within a defined window. The combination of cutting ultra processed food, cutting sugar, cutting alcohol and fasting has shifted 15kg without me ever feeling like I was on a diet. That's probably the most convincing evidence I have that this approach works, at least for me.

— Nick