Understandably, crash diets have long been popular with those who yearn to lose weight fast. There is no argument that starvation will result in weight loss. But what happens when we induce a metabolic starvation mode? And why do crash diets fail?
Simply put, temporary starvation slows the metabolism. The basal metabolic rate declines and our physiology slows as well. Not surprisingly, the dieter feels tired, sluggish and cranky.
Here’s what is occurring behind the scenes of that promising new crash diet. Since the body must start consuming its reserve energy (fat), it enters a period of extreme metabolic economy. Since there is a metabolic fuel shortage, mitochondria tend to shrink and go ‘offline’ in the interest of preserving this economy. If you keep to starvation mode, long-term, through ingestion of a very-low calorie diet, the metabolism rebounds.
Typically, however, starvation mode ends and food intake is resumed. You might think, ‘hey, that doesn’t sound so bad for a dieter,’ but you’d be wrong and here’s why.
Under the context of starvation induced slow-metabolism, the first priority of our physiology is to restore the reserves that were consumed. So even resuming a ‘normal’ calorie diet after a short period of starvation will result in rapid weight gain. Starvation also puts your health at risk with other possible complications such as vitamin and mineral deficiencies, hormonal imbalance and the potential for psychological and behavioral disorders related to food.
If we have fat reserves, it seems like starvation would be good, right? Well, it’s not so simple. The heart and skeletal muscles are efficient users of mobilized fat energy, but the brain and central nervous system are strict metabolizers of glucose, not fat.
So, during the starved state, the body focuses on making glucose for the brain, not mobilizing fat for the muscles. This keeps you alive, but muscle metabolism shrinks because mitochondria shrink in size and population. This state is often referred to as a shrunken or slow metabolism and it can have a lasting negative impact on your health. And the most irksome piece of this puzzle? Your altered metabolism makes it easier to gain weight and hard to lose weight in the future. Exactly what you were trying to avoid!