From intermittent fasting to time-restricted and periodic fasting, here’s your go-to cheat sheet for fasting diets
However, the health benefits of embracing rather than fearing hunger have been increasingly recognised and are challenging the traditional three-meal, two-snack mindset.
Fasting, whether it’s for a few hours a day, or a few days, a week or a block of days every few months, is not just about weight loss, or necessarily about weight loss at all, but about potentially preventing major killer diseases such as diabetes and cancer. Fasting increases fat loss, specifically of visceral fat - the dangerous type that clings to our middles and that has been linked to increased risk of type 2 diabetes, heart disease, certain cancers and Alzheimer’s.
Fasting has also been associated with improved blood pressure and insulin sensitivity, better gut health , lower cholesterol and increased cognitive function as well as supporting an important repair process in the body called autophagy, which only happens when in a fasted state. "Autophagy simply means self-eating, a process that every cell in your body goes through," explains Cosmetic Dermatologist Dendy Engelman. "Processed foods and environmental toxins can slow autophagy down, so to combat that, you can activate the process through different eating habits, such as intermittent fasting." Think of autophagy as a ‘time-out’ or the ‘repair mode’ that allows the body the chance to rid itself of a buildup of cellular debris, too much of which can increase the risk of age-related diseases such as arthritis and type 2 diabetes.
Fasting isn’t for everyone though, and children and pregnant women should steer clear as should those who suffer from adrenal fatigue or eating disorders. Those who have medical issues should seek advice first.
So where to start to access all these wonderful benefits? There are three main types of fasting and the length of time spent in a fasted state can determine the range of benefits obtained (to harness the benefits of autophagy for example, you need to not eat for a minimum of 12 to 14 hours, whereas it only takes five hours, such as not snacking between meals, to improve your gut microbes and insulin sensitivity). Here’s our guide to which fasting diet plan does what.
1. Intermittent fasting
Fasting only on certain days of the week.
The 5:2 diet : aka The Fast Diet, the best known of the fasting methods made famous by Dr Michael Mosley . Comprising of five days of regular eating and two ‘fast’ days of 800 calories, it’s been associated with improved DNA repair and brain function in addition to the benefits mentioned above plus, an increase in fat loss as demonstrated in a 2011 Manchester University study. Dr Mosley lost 20lb in 12 weeks and saw his blood sugar and cholesterol levels returned to normal after being pre-diabetic and suffering from high cholesterol.
The 1:1 diet: aka Alternate Day Fasting. Published as The Every Other Day Diet by Dr Krista Varady and Bill Gottlieb, it involves eating 500 calories every other day. You’re able to eat what you like during the fast, provided calorie intake is limited on the fast days.
The 6:1 diet: Made famous by Coldplay’s Chris Martin, this diet involves completely fasting for one day and eating as normal for the rest of the week. It sounds like the simplest diet within this category, but it’s the least substantiated as it isn’t advisable to fast without any food (or just drinking water), as you’ll most likely lose muscle as a result.
2. Time-restricted feeding
Downsizing your meals from three to two or even one a day, or only eating within a ‘window’ of time (often eight hours). You can find out more about Time Restricted Eating (TRE) here.
The 2 Meal Day: Created by personal trainer and online health coach Max Lowry, this plan involves skipping one meal (either breakfast or dinner) and extending your night fast (that is, while you’re sleeping) to around 16 hours. Read more about the 2 Meal Day here .
The Warrior Diet: Published by Ori Hofmekler in 2001, and involves one meal per day in the evening. The idea is to emulate the way our warrior ancestors ate their ‘hunt’ at night to distribute ‘undereating’ and ‘overeating’ throughout the day accordingly. Its emphasis is placed on whole foods and whole grains.
How to Lose Weight Well: Published by Dr Xand van Tulleken (who himself lost six and a half stone doing it), this evening meal focused plan can be adapted to best suit your lifestyle and objectives. To help achieve faster weight loss and the benefits of intermittent fasting, it recommends one 800-calorie meal a day or if that’s too infrequent, two healthy meals a day of 1,200 calories or three meals of 1,500 calories.
Metabolic Balance: Founded by Dr Wolf Funfack, this diet plan claims to aid weight loss and improve sleep, digestion and energy levels by advocating a five-hour fast in between meals over a three-month time period. Provided by nutritional therapists on a widespread scale, it’s also favoured by Sam Smith and Kirstie Allsopp.
16:8: aka The 8-Hour Diet. Published by Men’s Health Editor David Zinczenko and Peter Moore, this plan comprises of 16 hours fasting and an eight-hour window to eat in.
3. Periodic fasting
Fasting for a few days or weeks at a time.
Fast Mimicking diet: Devised by a company called ProLon, the inspiration behind this plan’s name derives from its objective to support the body while convincing it that it’s fully fasting at the same time. Created by Professor of gerontology and biological sciences at USC, Valter Longo, it comprises of meal boxes designed to be used for 5 days every month. Using natural, gluten-free and plant-based ingredients, meals are low-protein, low-carb and high in good fat, with 770 to 1,100 calories aimed for per day.
The Bodhimaya Method: Founded by brothers Daniel and Cornelius O’Shaugnessy, the method combines the format of the 16:8 plan (outlined above) with a fast day food plan portion ratio of 1:7:2 (carbs to veg to protein). Find out more about The Bodhimaya Method here .
Buchinger Wilhelmi: A selection of medically supervised fasts starting from a minimum of four days (10, 14 and 21 day programs are also available). Fast days feature small amounts of food (of around 250 calories) and a carefully regulated exercise plan to prevent muscle loss.
8-weeks: aka The Blood Sugar Diet. Created by Dr Michael Mosley, this plan has been devised specifically to prevent and reverse type 2 diabetes and involves eating three small meals totalling 800 calories for eight weeks.
Read more: why not all calories are created equal