INTERMITTENT FASTING DIETS

INTERMITTENT FASTING DIETS - THE LOW DOWN ON WHAT THEY INVOLVE AND HOW WELL THEY WORK. PLUS A NOVEL "IFD WITH VARIETY" IDEA

The following is an adapted excerpt from my new comprehensive evidence-based healthy lifestyle guidebook “Eat, Move, Sleep, Repeat” which is being published by Meyer & Meyer Sport. The book describes the pros and cons of many weight loss diets and this article describes my thoughts on the currently popular intermittent fasting diets. My book will be available later this year and you can pre-order your copy from Amazon now via this link: https://www.amazon.co.uk/Eat-Move-Sleep-Repeat-Fitness/dp/1782551875/ref=sr_1_1?crid=1R3EQI16R1CCN&keywords=eat+move+sleep+repeat&qid=1561723790&s=gateway&sprefix=eat+move+%2Caps%2C139&sr=8-1

Intermittent fasting diets (IFD), of which there are several, have become popular in recent years, in part because of a lot of media coverage and backing from television and film celebrities. However, there is reasonable evidence that they can be effective, as all of them will reduce weekly energy intake to some degree. They may not be quite as beneficial for women as men and may also be a poor choice for people who are prone to eating disorders. It is also important to bear in mind that you should aim to eat healthily as well (see chapter 4 for details) during the normal eating phase of the diets.

The alternate-day fasting diet means fasting every other day. This can be a complete fast, or some versions of this diet allow you to consume up to 500 kcal on the fasting days. A full fast every other day seems rather extreme and could lead to insufficient protein intake with negative consequences for muscle mass, so it is not recommended for athletes and other highly physically active people. The version where you eat normally on four days of the week and consume only about 500 kcal on alternate days is sometimes referred to as the 4:3 diet. A less extreme version of this IFD diet is the 5:2 diet (also commonly known as the “Fast Diet”), popularized by the British television medic Dr Michael Mosley, which involves eating normally on five days of the week, while restricting intake to 500 kcal (for women) or 600 kcal (for men) on two days of the week (usually these are separated by two to three days such as fasting on Mondays and Thursdays). On the fasting days (note this is not strictly fasting, rather just eating much less than normal on two days of the week), you could eat two small meals (250 kcal per meal for women, and 300 kcal for men). These should be high-protein meals for better satiety (as mentioned in chapter 6) and to maintain muscle mass. Even so, the very low energy intake on the semi-fasting days of the 5:2 and 4:3 intermittent fasting diets will almost certainly not provide sufficient protein and micronutrients to meet minimum daily requirements. This can be compensated for by having a high-protein dinner on the day before the semi-fasting day and a high-protein breakfast on the day after. A slightly less drastic version of these two IFDs with a lower risk of consuming inadequate amounts of protein is to allow up to 800 kcal on the fasting days. Dr Mosley has more recently promoted a modified version of the 5:2 diet in which he recommends a healthy Mediterranean diet (see chapter 4 for details) on the non-fasting days. This is a very sensible recommendation in my opinion, especially if it incorporates some high-protein and low energy density meals on the non-fasting days (see later in this chapter for the reasons why). Alternatively, for a change of foods and flavours, you could try adopting the Japanese diet on the non-fasting days.

Another IFD involves fasting from evening dinner one day to dinner the next (i.e., skipping both breakfast and lunch for a day), amounting to a 24-hour fast, and doing this on two days of the week. You should eat a normal meal at dinner on these days and not compensate for your hunger by eating more than usual; eating slowly and having a high-protein meal will again help with satiety. Another simple IFD is to skip one meal (usually lunch) during the day.

The Warrior Diet was popularized by ex-army fitness expert Ori Hofmekler and involves eating small amounts of raw fruits and vegetables during the day, then eating one large meal in the evening. The diet also emphasizes food choices (whole, unprocessed foods) that are quite similar to a Paleo diet (described later in this chapter) in which you are encouraged to eat anything we could hunt or gather way back in the Paleolithic era (also known as the Stone Age), including foods like meats, fish, nuts, leafy greens, regional vegetables, and seeds but avoiding processed foods, ready meals, pasta, bread, cereal and candy.

Another type of IFD is what is known as time-restricted feeding. This is a daily eating pattern in which all your food is eaten within an 8-12-hour timeframe every day, with no deliberate attempt to alter nutrient quality or quantity. This usually involves abstaining from breakfast, thus extending the duration of your normal overnight fast (the time when you are asleep and not eating), which gives your body more time to burn fat and do essential repairs. Outside of this time-restricted eating period, a person consumes no food items apart from drinking water or low-calorie beverages to stay well hydrated. Such beverages could also include black unsweetened coffee or green tea (without milk). Time-restricted eating is a type of intermittent fasting because it involves skipping breakfast or both breakfast and lunch. It is a pattern of eating that probably is similar to what our ancient ancestors adopted: most of the daytime would be spent hunting and gathering food, and most of the eating would take place after dark.

Although time-restricted eating will not work for everyone, some may find it beneficial. Some recent studies have shown that it can aid weight loss, improve sleep quality, and may lower the risk of metabolic diseases, such as type 2 diabetes. Modern humans, due to societal pressures, work schedules, and with the availability of night-time indoor illumination and entertainment, stay awake longer, which enables food consumption for longer durations of time. This extended duration itself, in addition to the caloric surplus, can be detrimental to health by reducing sleep time. A recent study using a smartphone app to monitor eating time has revealed more than 50% of adults spread their daily food and beverage intake over 15 hours or longer. Such extended eating of high fat or high or high glycemic index diets is known to predispose laboratory animals to metabolic diseases.

It is probably best to start a time-restricted eating plan gradually. Try starting with a shorter fasting period and then gradually increasing it over time. For example, start with a fasting period of 10:00 pm to 6:30 am. Then increase this by one hour every two days to reach the desired fasting period (usually around 8:00 pm to 1:00 pm the next day – leaving a time-restricted eating period of seven hours). Studies have suggested that restricting feeding periods to less than six hours is unlikely to offer additional advantages over more extended feeding periods.

The largest evidence base for the efficacy of IFDs derives from studies that have used some of the more extreme forms, such as alternate day fasting, which, according to several studies, can lead to significant body weight loss amounting to 3-8% over a period of 3-24 weeks. With alternate-day fasting the rate of weight loss averages about 0.7 kg/week (1.5 lbs/week); with other IFDs the rate of weight loss is less at about 0.25 kg/week (0.5 lbs/week). Studies comparing intermittent fasting and continuous calorie restriction show no difference in weight loss if calories are matched between groups.

The IFD With Variety (illustrated in the Figure accompanying this article) is a unique plan that is my own invention and I believe it will suit many people. You consume only 800 kcal on two days of the week (Monday and Thursday). These IFD days are preceded by a high protein diet day supplying 1600 kcal on Sunday and Wednesday. On Tuesday and Friday you consume 2000 kcal which is enough to most people’s resting daily energy requirement but you eat diets that are known to be very healthy, namely the Mediterranean and Japanese diets, respectively. Finally on Saturday you eat the Flexitarian diet which is another healthy diet that is primarily plant-based, of low energy density and voluminous but allows you a choice of a small portion (up to 6 ounces) of lean meat, poultry or fish and comes in at 1700 kcal. In total this seven-day IFD With Variety generates a 3500 kcal energy deficit which should result in a loss of 1 lb of body fat tissue. Keep it up for 10 weeks and you will have lost over 10 lbs in weight. The big advantage of including multiple diets in your weekly meal plan is that you will not get fed up (pardon the pun!) with dieting, you will not get food cravings, you will get all the essential nutrients you need as well as plenty of those non-essential but health promoting nutrients fibre and phytochemicals. All this means that you will be eating healthily with lots of variety and will be much more likely to stick to your weight loss plan. Full details of all the diets described in this article, together with many example meal plans, plus how to combine dieting with exercise to optimize body fat and weight loss can be found in my new book Eat, Move, Sleep, Repeat available to pre-order now from Amazon via this link: https://www.amazon.co.uk/Eat-Move-Sleep-Repeat-Fitness/dp/1782551875/ref=sr_1_4?qid=1565424538&refinements=p_27%3AMichael+Gleeson&s=books&sr=1-4