Fasting as a concept is not new and has origins in energy restriction increasing the lifespan of animals. This has then led to a wealth of experimental insect, invertebrate and animal studies, and a more recent array of human intervention trials. More recently, intermittent fasting (IF) emerged as an incredibly popular dietary approach for weight management and health. Practically speaking this is individuals undertaking periods of fasting or severe energy restriction, interspersed with periods of non-fasting or free (ad libitum) eating. The two main forms of intermittent fasting are intermittent energy restriction (IER), and Time Restricted Feeding (TRF). IER typically involves 24-36hour total or partial alternate days of the week, or 2 days out of 7 (such as in the 5:2). TRF is the most recently advocated version IF and has interesting connotations from both the metabolic perspective and the chronobiology perspective as it involves manipulating the meal/energy pattern within a 24-hour cycle. Practically speaking this involves reducing the “eating window” to typically only 8 hours of the day, or may include other approaches such as meal skipping.
An inherent feature of IER is that individuals typically causes people to eat less calories overall even when free eating on non-fast days or times. This makes IER a very effective form of weight loss that is comparable to traditional continuous energy restriction. Beyond weight loss, both forms of intermittent fasting (IER and TRF) elicit other distinct metabolic, and behavioural advantages which makes it a dietary intervention of interest beyond simply weight loss. Particularly in relation to improvements in lipid metabolism (e.g. Postprandial lipid clearance). However, there may also be adverse effects of IF. IER in particular may contribute to some metabolic dysfunction, for example, temporal glucose intolerance, possibly as a consequence of mitochondrial lipid overload. Moreover, behaviourally, intermittent fasting may, by its nature, exacerbate disordered eating in some individuals. Hence advocating IF needs to be done with some consideration.
What will I gain from watching this webinar?
- Differentiate types of intermittent fasting (IF)
- Analyse the effects of IF on weight loss, metabolism and behaviour
- Take away practical application considerations for introducing IF.
