In the past, it was believed that weight management was simply a matter of calories in to calories out. In other words, consume fewer calories and expend more, perhaps increasing your exercise, and bingo, the weight will come off.
But, as many have discovered, it is not quite as simple as that.
If you cut down on calories, your body will respond.
On a day to day basis, your body uses glucose as a source of energy. This comes from sugar and carbohydrates you consume. And stores in the liver and muscles. If you eat less than you need, your body will look for other sources.
One readily available source is protein. Amino acids in protein can be converted in the body to glucose, and enter the usual metabolic pathways to produce energy.
Unfortunately, this can mean that you lose muscle mass, as the protein in your muscles is burned for fuel. The end result is that you finish your diet program with less muscle mass, with a correspondingly lower metabolic rate. Return to a normal diet and you will gain weight.
Another problem with severely cutting down on calories is that your body will go into starvation mode, causing a boost in cortisol, which promotes the storage of fat in the abdomen. Now that is the worst fat to store in your body.
So, what else can you do if you want to lose excess fat?
What a ketogenic diet does is to train the body to burn fat instead of glucose.
Our bodies are equipped to utilise fat for energy. Otherwise we would not store excess calories as fat. But the body prefers to use glucose as the energy supply is instant and conversion is very efficient.
To switch over to burning fat, you need first to deplete your body of carbohydrates, the body’s preferred fuel source. The body will then look for alternative sources of fuel.
It may start to use protein, but within a couple of days the biochemistry will switch over to utilising fat. The body will convert the fats into ketones which can be used to produce energy. This is termed ketogenesis. When you are using ketones as a fuel source, you are said to be in ketosis.
Those first few days you can feel tired and flat. But once you settle into ketosis, your energy levels will lift, you will feel alert. Best of all, you will cease to feel hungry.
NO hunger! Because the body is utilising ketones rather than glucose, insulin levels are stabilised. It is the peaks and troughs of insulin levels following the consumption of sugars and carbohydrates that can lead to dips in energy levels and feelings of hunger.
If instead of following a ketogenic diet, you continue on a low calorie diet, but continue to eat carbohydrates, this switch will not occur. Instead, your body will preferentially consume the carbohydrates, and then the protein and fats indiscriminately, leading to muscle wastage.