Posted on 2019-10-31
Great for those with a regular lifestyle and routine. Eating through an 8-hour window of your day, and fasting for 16.
You can tailor the window around what meals you value the most, and when you tend to have the most time to eat. Most people skip breakfast and start eating at lunchtime, finishing up with dinner. This sits in line with when most of our hormone levels make us hungry (and skipping dinner is generally quite antisocial).
The reason most people eat breakfast is habit that stems from a lifetime of marketing that has told us it’s the most important meal of the day. That’s a lie created by Nestle and Kellogg’s to sell you as much of their addictive sugar as possible.
The 16:8 diet is a good way of finding out if for you that is the case, though until you've done it for a matter of weeks you can't be conclusive. You may happen to be one of the few that genuinely needs to eat breakfast early in the morning as part of their daily routine.
It often results in weight loss because most people are removing up to a third of their food. Breakfast can be 15-35% of their daily calories, so it’s much easier to get into the deficit needed for a reduction in stored fat. This assumes one can exercise self-control and not “undo” the skipped meal by eating more the rest of the time.
There’s a possibility 16:8 isn’t quite as effective as it’s marketed to be though. Some purists argue that because we spend up to 8 of the 16 fasted hours asleep, it is much less relevant than 8 hours of woken fast. This is because one’s heart and metabolic rates are much lower during this period so the caloric burn is lower.
They argue that a more effective span would be more like 18:6. You won’t see this popularised though because of the inconvenience of starting “office lunch” at 1pm and finishing dinner before 7pm.
One note on this, is studies have shown your brain derives benefits from sleeping with no food in the gut. Even on and 18:6 an eating window like this once a week alone, to ensure you have more time between dinner and bed, would be beneficial.
16:8 or 18:6 may not work for you for a few reasons though. First of all, you may not have enough control over you schedule and not have time to break your fast at a regular time. Or, you may not finish work, and have dinner, until way after the window closes. Work events or social life may mean you also end up wining and dining on a few days of the week. Alcohol is still calories and drinks rarely end before 8pm when most people’s window would close.
One thing that is quite common is people trying 16:8 and getting into a great rhythm of it, and then letting one inconvenient day throw them off track. They beat themselves up about it and ditch the system. A day doesn’t matter, neither does two or three! You can even take every weekend off if weekend mornings mean pancakes with the family or some other tradition. Some fasted mornings are better than none and I actually prefer a slightly higher calorie intake on the weekend when people are more relaxed and able to fit in meals that require more time and energy to produce – just don’t take non-fasted weekends as full on “cheat days” and eat everything naughty because “hey, it’s the weekend!”.
Our recommended variation: 18:6, 5 days a week.
Lastly, build to it slowly. We'd recommend you start with eating breakfast later and later until you don’t eat until lunch, 16-18hrs after the previous dinner.
Head over to the next part of Intermittent fasting where we cover Intermittent Fasting IV - The Alternatives