What is crash dieting and do they work?

Tuesday, 7 January 2020  |  Admin

What is a crash diet?

The term 'crash' when referring to dieting can conjeur up visions of collapsing due to lack of energy due to eating too little and trying to lose weight too quickly. Whilst it may or may not have that effect, crash dieting or eating a severely restricted diet is unlikely to result in successful permanent weight control for many reasons.

Do crash diets actually work?

You may have made up your mind to take drastic action in order to shed some weight quickly, but your body will not understand this decision and when it’s usual supply of calories is not forthcoming, will initiate ‘anti-starvation’ measures to preserve energy.

One way the body does this is to slow down the metabolic rate or BMR, the rate at which energy is used to maintain essential bodily functions. It does this in order to preserve the body’s accumulated fat, which are part of its energy stores. As fat is what most people on a diet wish to lose, then this somewhat defeats the object of crash dieting. The slower rate of metabolism can also continue past the end of the diet which means when calories are re-introduced, they are not burned as quickly and the weight which was lost is rapidly restored, usually resulting in a heavier weight than before the diet was started. Taking all this into account, it is safe to say that crash dieting rarely works in the long term.

What does crash dieting do to the body?

A slowed metabolism can also trigger other responses within the body, which is naturally programmed to take advantage of any food source that becomes available. When food becomes available, processes are triggered to encourage binge eating as the body assumes it may be the last source of calories for quite some time and therefore demands a binge in order to obtain the calories it craves. This fact alone makes the chance of reducing weight long term through crash dieting, highly unlikely.

Although weight can be lost rapidly initially, this is likely to be in the form of fluid and muscle tissue rather than fat. As the body needs glycogen for energy, it will burn this from the liver and lean muscle tissue and as glycogen is stored with around 3-4 times its weight in water, rapid weight loss will register on the weighing scales, even though it is a loss of fluid rather than fat. This fluid, and its associated weight, will be rapidly replaced when normal eating resumes.

Insufficient glycogen in the body results in a lack of energy, making it difficult to take exercise and remain active, which would help to burn more calories in order to lose weight. Irritability, depression and fatigue are signs of low glycogen levels and negative emotions will not help with long term weight control.

Should I skip meals?

Skipping meals or eating very small meals are also not conducive to long term weight control as eating this way can also encourage overeating and binging when food becomes available. Binging is a natural response by a body that is undergoing a severely restricted calorie intake, which further reduces the chances of successful long term weight loss.

Apart from all of the above, crash or severely restricted diets can be nutritionally deficient and following them frequently can result in nutrient deficiencies that affect the health of the body, promote a pre-occupation with food and cause psychological issues that make the chances of successful and permanent weight control highly unlikely.

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