- 2 days of calorie restriction and 5 days of regular eating
- calorie restriction - 600kcal (men) and 500kcal (women) on non-consecutive days
The authors identify the regularity of dieting in society today and acknowledge its effectiveness for some individuals, but not all.
The word diet has a negative stigma. In many people's head it alludes to low calorie meals, no fat, minimal carbs and the tasteless torture of the vegetable aisle. However, consider the meaning of a healthy, balanced diet. Essentially it refers to giving the body enough of what it needs - everything!! The body needs saturated fats and carbs and all sorts to hum healthily. Too much of many things and the body has excess to deal with, becomes bogged down and needs a good service.
Anyway, back on track.
Initially, a couple of alarm bells began ringing in my head.
- when the calorie intake drops lower and lower, in this case well below a normal resting metabolic rate (the number of calories your body burns simply by being awake and still), it encourages the internal systems in a person to go into a 'survival mode'. The metabolic rate drops, the body preserves energy by slowing down, otherwise the vital organs will deplete the energy stores and the body is in severe risk of stopping.
- this follows on to the idea of yoyo dieting. The body will survive however it needs to and when a regular diet is consumed it will store more food and replace what has been lost - the weight goes back on
- finally, when carbs run out, the body breaks down fat but also protein. This protein as taken from the stores in the muscles. While this would most likely reduce weight, it will slow the resting metabolic rate and weaken the muscles, thus impairing the functional ability of an individual. Furthermore, it may lead to alterations in immunity.
"The evidence is limited"
Solutions?
Well, the authors seem to suggest that you make sure that the calorie restriction day contains plenty of protein. Easy! But is it that simple?
The others aren't any easy to find a solution. Not only that, but the NHS among others have reported a variety of anecdotal side-effects such as sleeping difficulties, irritability, anxiety and daytime sleepiness. Quite simply, with it being a new approach to dieting, the evidence is limited.
Summary (in my eyes!)
Pro's -
- Allows you to eat a healthy, non-restricted diet for the 5 days
- In total, it reduces the recommended intake for an individual by 3000-4000kcal per week which equates to around 0.5kg of energy per week
- some evidence suggests that not only is weight loss a benefit, but it also helps to reduce the onset of chronic diseases
- the evidence is limited - a lot of references are to research on mice
- it will not necessarily be suitable for everyone - see a GP first
Personal suggestion from a personal trainer...
I wouldn't recommend this diet to a client over traditional methods of healthy eating. I wouldn't dismiss it and call it a pack of lies since it may work for some people. Often a diet is used for a short/medium term goal such as a holiday/dress size as opposed to long term adherence and for this it may prove useful. However, I aim to get my clients to understand and get into a routine of healthy eating (quality and portion size) and regular physical activity so that the term 'diet' hopefully becomes obsolete. It is simply a healthy lifestyle