How to do Intermittent fasting | Intermittent fasting plan
Intermittent fasting(IF) is a fasting form attributed to various health-promoting effects on the metabolism. It is dispensed daily or hourly food. Usually, the goal is long-term weight loss.
In contrast to other forms of fasting Intervall fasting should be used as a permanent diet. The different forms of Intervallfastens differ in terms of duration and frequency of diet waiver. The following forms are known:
The 2-day diet (2-day-diet)
In 2013, the nutritionist Dr. Michelle Harvie and oncologist Prof. Tony Howell published the book “The 2-Day-Diet”. The diet was originally developed for breast cancer patients to help them lose weight with an easy-to-follow method.
For a 2-day diet, a maximum of 650 kilocalories will be consumed on two consecutive days within one week. The food selection should be low in carbohydrates and high in protein. Harvie recommends fish, chicken, egg, dairy, tofu, vegetables and fruits. For the remaining five days, she advises on a classic Mediterranean diet. In addition to the temporarily limited energy intake, a total of 40 energy percent from carbohydrates should not be exceeded.
The 5: 2 Diet (The Fast Diet)
The 5: 2 diet designed by Dr. med. Michael Mosley is one of the best known forms of intermittent fasting. The concept is based inter alia on the present results of Dr. med. Harvie.
This form of interval fattening is normal for five days a week. There are no specific recommendations for selecting or preparing food. This is intended to increase the compliance of the diet in persons who want to lose weight and to protect against a termination of the diet by overly strict regulations. On the two days of fasting is about a quarter of the usual energy intake “allowed”. Mosley recommends on the two days of fasting, especially vegetables and wholemeal cereals such as brown rice or oats, as well as high-protein foods and plenty of fluids. The fast days should follow a fixed rhythm, for example on Mondays and Thursdays.
Alternate Day Fasting (Every-Other-Day Diet)
Another variation of the Interval Fattening is Alternate Day Fasting (ADF), also known as “eat stop eat”, “updaydownday” or “alternate fasting”. The concept was published by Krista Varady in 2013 in the book “The Every-Other-Day Diet”.
The principle of the diet is based on only about 25% of the usual amount of energy on the days of fasting. On non-fasting days, there are no restrictions on energy intake.
Also the dinner canceling is a form of the Intervallfasts. This concept dispenses with dinner two to three days a week. In the evening only water, tea or other calorie-free drinks are drunk. This results in a meal break of at least 14 hours until breakfast.
Evening fasting is designed to relieve insulin levels, promote weight loss and improve sleep quality. In addition, it should reduce aging processes and thus prolong life.
Other variants of the Intervallfastens are “Leangains”, which is due to the omission of the breakfast, a fasting time of about 16 h and the Warrior diet, in which only a meal is taken in the evening. Fasting during Ramadan is also a form of interval fattening.
Intermittent fasting – an overview of the scientific study situation
Results from animal studies indicate that regular dietary abandonment can reduce the risk of chronic disease. These include diabetes mellitus type 2, cardiovascular diseases, neurological diseases and cancer. The brain function could also be positively influenced by intermittent fasting. In addition, interval fasting (alternating fasting) shows life-prolonging effects in animal experiments (Kaeberlein et al., 2006, Longo and Mattson 2014). The authors of a recent study in mice found that prolonging life by alternately fasting is not associated with a general retardation of the aging process but with delays in life-limiting neoplastic disorders (Xie et al., 2017).
Clinical human studies on the effect of Intervallfastens are so far only in small numbers and are not unique in their statements. A recent meta-analysis presents various hypotheses about intermittent fasting to affect the metabolism. These include circadian biology, intestinal microbiome and alterable lifestyle factors such as sleep patterns (Patterson and Sears 2017). There are also no clinical studies comparing the effect of intermittent fasting on periodic fasting (Mattson et al., 2017).
In a review from 2015, the authors conclude that the data from the few existing clinical studies and observational studies provide evidence of positive health effects (Horne et al., 2015). The authors of another meta-analysis from the same year conclude that intermittent fasting is a valid alternative to continuous energy restriction, as compared to continuous energy restriction for weight loss, fat mass, lean mass and improved glucose homeostasis (Seimon et al. 2015).
Especially with regard to loss of fat-free mass, interval fasting seems to perform well compared to a diet that is continuously energy-reduced. While similar losses in body weight and fat mass were observed after 3 and 12 weeks respectively, volunteers in a human study lost less fat-free mass through interval fasting than with an energy-reduced diet (Varady 2011). Harvie showed that intermittent fasting with limited energy and carbohydrate content is superior to a continuously reduced energy diet in terms of improved insulin sensitivity and body fat reduction (Harvie et al., 2013).
Recent studies, however, came to the conclusion that the interval fasting in its effect is not or only slightly different from other diets. In ten healthy men during Ramadan (28 days), the effect of food withdrawal over 14 hours daily was studied. Only very small effects on the body mass index (BMI) and no effects on body composition, glucose metabolism and cognitive function were observed (Harder-Lauridsen et al., 2017). A literature review on the effects of fasting in Ramadan found that after the end of Lent the parameters in healthy people usually return to pre-Lent levels (Richter 2017).
In a recent, randomized clinical study of 100 adipose and metabolically healthy adults (mean BMI 34), daily energy restriction (-25% of energy demand) was compared to alternate fasting (fast day: 25% of the energy required, day of eating: 125% ). The drop-out rate for alternate fasting was greater (38%) than for daily energy restriction (29%). The weight loss was not significantly different in both diets after 6 and 12 months, respectively. There were also significant differences in blood pressure, triglyceride concentration, fasting glucose, fasting insulin, insulin resistance, C-reactive protein and homocysteine concentrations at either 6 or 12 months. In the group of alternate fasting was after 6, but not 12 months, only the HDL concentration significantly increased compared to the other diet group. By contrast, at 12 months, the subjects’ LDL concentration in the fasting group was significantly higher (11.5 mg / dl) than in the group with continuous energy restriction (Trepanowski et al., 2017).
Due to the lack of data, no reliable statement can yet be made on the extent to which interval fasting leads to an improvement in the glucose metabolism. Alternating fasting for 8 weeks resulted in a slight weight loss in a human study (-4% compared to baseline), but did not affect glucose homeostasis (Varady 2016). Compared to moderate fasting of 5,000 to 6,500 kJ / d, interval fasting was almost identical in both weight loss and glucose metabolism parameters (Carter et al., 2016).
Conclusion and nutritional evaluation
Intervall fasting is a method that is currently heavily promoted in the media for weight loss. It differs from a fasting cure in that it should also be used over the long term. Differences between the different forms affect frequency and duration of abstinence.
The evaluation of the clinical human studies available so far is not only due to the many different forms of intermittent fasting (alternating fasting, 5: 2 fasting, etc.), but also by the various study populations (overweight, normal weight, obese) and by the small study population difficult. In addition, there are no scientific studies on the long-term effects of interval fattening.
The data to date suggest that intermittent fasting may have a positive effect on health and weight loss, in particular less fat loss, or seems to be on a par with continuous energy restriction and has no negative side effects. Whether the compliance in comparison to other forms of diet is greater, remains to be seen. Studies, especially long-term data and with a sufficiently large study population, are also missing. To what extent intermittent fasting influences other parameters such as mood, exercise capacity, cognitive performance or the risk of eating disorders can not currently be assessed.
Most concepts of interval fattening contain no or very vague food selection recommendations. As a result, intermittent fasting alone generally does not result in a dietary change to a food-physiologically favorable food selection.