On numerous occasions I’ve been asked by my clients why, like some other personal Trainers, I don’t prescribe a High Protein-Low Carbohydrate Diet to shred the body fat. This article highlights some of the reasons why I cannot condone such practices.
High-protein, low-carbohydrate diets promote weight loss by inducing KETOSIS. This is the same toxic state that diabetics suffer during starvation. Ketosis produces KETONES; these are a by-product of the body not sufficiently breaking down fats.
The official definition of ketosis as given by The Encyclopaedia from NHS Direct Online is:
Ketosis is the presence in the blood of abnormally high levels of acidic substances called ketones. The normal body fuel is glucose. Ketones are produced when there is not enough glucose in the bloodstream, and fats and protein have to be used. When proteins are used excessively as fuels, they are eventually converted to ketones. The real danger in ketosis is that ketones are acidic, and high levels of ketones make the blood abnormally acidic
The ideal way to burn fat is to use carbohydrates as an accelerant, however when the body has insufficient carbohydrates to breakdown into glucose, it is forced to use stored fats and protein as an energy source. Major organs and the brain are forced to utilise ketones as the primary energy source in the absence of the essential carbohydrates. This ketone utilisation by the brain has been linked with subjects feeling lethargic, over tired and depressed, with a loss in strength and stamina.
Among the unfortunate and not-so pleasant side effects of ketosis are: constipation and bad breath. There is a rapid short term weight loss during the high protein diet; this is in part due to the loss of body fluids as a direct result of the low carbohydrate. The main reason for this is that the body is slowly depleting all the stored glycogen from the liver, kidneys and muscle fibre, along with excreting toxins via the urine. Many people mistake this rapid water loss, which occurs in the first 7 to 10 days as body fat loss. In reality it is fluid loss due to frequent urination and carbohydrate depletion.
Though there has been evidence to suggest that over a six month period, the high-protein, low-carbohydrate diet promotes rapid weight loss in comparison to a low at diet (published in the New England Medical Journal); there is no long term evidence to suggest that the weight loss can be maintained. Over a long period the diet may contribute to the onset of chronic conditions such as osteoporosis, cancer and kidney diseases.
This type of diet also promotes cutting out milk and other dairy products which is essential for maintaining calcium levels. Calcium levels actually drop as a result of the diet as excess urination excretes more calcium from the body.
A high protein diet may also place extra burden on the kidneys. The kidneys are responsible for clearing the body of waste products produced during protein metabolism. Ingesting large amounts of protein places extra strain on the kidneys and may have unfortunate consequences.
Low carbohydrate diets also prohibit starchy vegetables and the fibre that accompanies these vegetables. Fibre reduces cholesterol and facilitates excretion of body waste thereby promoting a healthy colon.
Finally there is no quick fix to weight loss, the simple weight loss equation is: Output must exceed input. So you need to burn more calories than you consume through limiting portion size and exercise. And remember that excess protein turns to fat and is stored by the body as fat, so overloading on it is counter productive to weight loss. Lets not forget why we take protein supplements; protein is there to repair muscle. If we use the protein as a fuel, muscle repair will suffer and the body will draw energy from the muscle itself as muscle protein is far quicker for the body to access.