Let’s be honest: Fasting can be HARD. Especially the shorter fasts.

HUH? Did I just say the shorter fasts are more difficult?

Shorter fasts – and fasts where you get to eat, say, 500 calories on alternate days – are much, much harder than longer fasts where you eat nothing at all for a few days.

Let me explain why, because this absolutely makes sense when you think about it.

WE’RE HUNTER-GATHERERS. WE’RE BUILT FOR FASTING

Our bodies are adapted beautifully for fasting. We evolved as hunter-gatherers, our main source of calories was animal foods through hunting, and we’d often goes days or sometimes weeks without much to eat.

Also, our food was seasonal. As anyone who has ever grown a fruit tree would know, nature often provides food in gluts. You either have no peaches or enough peaches for the entire neighbourhood! You either had enough wild buffalo meat to stuff yourself and your tribe, or the buffalo were nowhere in sight. That’s how nature works.

Before modern farming (10,000 year old farming techniques are “modern” to our hunter-gatherer bodies, remember!), our bodies were beautifully adapted to all this by putting on fat when we ate to the point of stuffing ourselves, then living off our fat in lean times in between successful hunting.

Women were – and are – able to store fat even more efficiently than men, because we needed to be able to carry children, give birth and feed them. It all makes sense.

Except now we don’t fast any more, because food is so ridiculously plentiful now that obesity is more common than underweight in the world.

I’m not saying this is bad or good, but it’s the way things are now. If we want to lose weight, it makes sense to return to old patterns of eating and to tap into the eat-fast cycles that our bodies are well adapted to.

WHY ARE SHORTER FASTS MORE DIFFICULT?

Shorter fasts are more difficult because they’re not true fasts. Our bodies keep expecting food, our insulin and ghrelin levels never truly level out, and our bodies never fully move into a fasted state. They’re kept in a limbo – not quite fasted, not quite fed – with the result that hunger is more difficult to manage and the benefits of true fasting never emerge.

WHAT ABOUT ALTERNATE DAY FASTS – WITH 500 CALORIES?

Several “alternate day fasting” programs allow up to 500 calories of food on the “fasting” days, as evidence seems to suggest that those 500 calories do not interfere with weight loss.

Maybe, but I speak from experience that when I tried one of these programs, on the 500 calorie days all I could think about was food. I was hungry all the time. I spent the whole day fantasising about what I might eat, and obsessing about those 500 calories. It wasn’t pleasant.

Eventually – a couple of weeks into the program – I slid off it. With no weight loss to speak of.

Now there seems to be evidence coming out that suggests that people on these programs end up much hungrier than if they ate zero calories on their fasting days. I’d agree with that. I think you’re better off fasting properly, and eating nothing on fast days. It’s much easier.

HOW HARD ARE LONGER FASTS?

Not as hard as you’d think. I’ve found on 3-4 day fasts that the hardest day is day 1, about mid-afternoon. My body hasn’t yet realised I’m fasting, and I’m starting to get hungry because I’ve missed lunch.

At this point, I drink a fair amount of water – at least a litre (four cups) – over an hour or so, and sometimes more. It gives me something to do, and fills me up. It also seems to trick my body into thinking I’ve eaten.

In the end, the only way to figure out what you find hard is to try different lengths of fasts, and see what works for you.