Intermittent fasting
Should I fast?
Intermittent fasting is an optional extra. If you naturally skip breakfast, or find yourself accidentally missing meals, or just aren’t hungry sometimes then you might be interested in giving intermittent fasting a try. If you’re a “three square meals a day” person then you may well feel that fasting isn’t for you. I do think it’s worth finding out more about it though because it can be another tool in the weight loss tool box. When you’re near your target weight and those last few pounds are taking ages it might be something you want to try to see if it aids weight loss.
What are some advantages of fasting?
- Reducing hunger. Completely counter-intuitive, I know, but some people (myself included) find that if they skip breakfast then they are less hungry throughout the day. This can be due to the interaction between the stress hormone cortisol and insulin, perhaps caused by poor sleep quality or high stress/anxiety levels.
- Aids weight loss and doesn’t slow the metabolism. Cutting calories on a low-calorie diet is renowned for slowing the metabolism down but this doesn’t happen during fasting, in fact the metabolism can actually speed up.
- Improves insulin sensitivity and therefore blood glucose control – especially useful if you have or are at risk of diabetes.
- Decreases inflammation, lowers blood pressure, improves cholesterol and triglyceride levels.
- May help prevent dementia and cancer, delay aging, and improve longevity.
What are the different types of fasting?
16:8 means fasting for 16 hours overnight. So, if you have dinner at 6 p.m. then you don’t have breakfast until 10 a.m. the next day. The health benefits start from 14-hour fasts so I suggest aiming for 14 hours to begin with and working your way up to 16 hours. It only takes one or two fasts to get into the swing of things. What usually happens is that you feel hungry at your usual breakfast time and then the hunger passes within about 20 minutes. N.B. if you skip breakfast then you don’t need an extra big lunch to make up for the missed meal; eat your normal amount of food. I recommend paying attention to your body’s signals while fasting. If you’ve done 15 and a half hours and you’re starving then don’t hang on for an extra half an hour just to make 16 hours. As you get used to fasting the length will increase by itself. Aim for a minimum of three 16-hour fasts per week.
You also get longer daily fasting windows – 18:6, 20:4, even OMAD which stands for One Meal A Day and is effectively 24-hour fasting. The ideal fasting window is 16-36 hours after which the benefits don’t continue to increase. I suggest that people experimenting with intermittent fasting try a 24-hour fast at least once. It’s instructive to find out that you can go without food for a whole day and you won’t feel particularly hungry or need to stuff yourself at the end of the fast. The easiest way to do a 24-hour fast is to eat your dinner one day and then don’t eat again until the next day. Make sure you drink plenty of (calorie-free) fluids as you will be thirstier than usual since you are missing out on the considerable amount of liquid you usually get in food. Every time you feel hungry then have a drink. If you feel very hungry then wait 20 minutes and if the hunger doesn’t pass, it’s probably time to end the fast.
Alternate Day Fasting is often the next step for someone that routinely fasts 16:8. It usually consists of three 24-hour fasts per week on non-consecutive days and can be combined with 16:8. So Monday you eat lunch and dinner, Tuesday you just eat dinner, Wednesday you eat lunch and dinner, etc.
What is the 50-calorie rule?
As a rule of thumb, many people say that you can have up to 50 calories during your fast period. This isn’t really true fasting but it does allow you to have a couple of cups of tea or coffee with milk while you’re fasting. It’s up to you how flexible you want to be. Personally, I hate black tea and I’m a total caffeine addict so I need a couple of cups of tea to get me through to brunch/lunch.
What are the risks?
Intermittent fasting is often not suitable for people who have had an eating disorder. You'll know if this applies to you.
If you’re routinely missing meals and your calorie intake is low then you could end up short on vitamins and minerals. This shouldn’t be a problem on Bootcamp where we’re emphasising real, unprocessed foods with plenty of salad and/or veggies. Make sure you’re getting a wide variety of foods and not relying on nutrient-poor food choices like bulletproof coffee.
When should I start?
I know some people have already tried fasting or are about to give it a go. If you're not sure about it then why not see how things go for the next few weeks with those Bootcampers who are fasting. Then when the ten weeks of Bootcamp are up we could have a follow-on thread for people that would like to give intermittent fasting a try. Whatever you decide, don't be pressured into thinking that you need to fast. As I said at the beginning, it's totally optional.
Any questions?