If you dramatically reduce the level of carbohydrate in your diet, sooner or later you will have to face the dreaded low carb flu.
Low carb flu is a period of flu-like low energy which normally lasts for anywhere from a couple of days to a couple of weeks although for some people, can last much longer.
All carbohydrates are converted to simple sugars, mainly glucose, in the digestive system. The glucose is transported to cells in need of energy by insulin where it is converted to smaller molecules and energy is released. If there is a lot of glucose in the bloodstream, insulin responds by taking it off to fat cells for safe storage because high glucose levels are highly toxic to cells – just think about the long term damage done by untreated diabetes – heart disease, strokes, blindness and nerve damage. Bear in mind also that a high carb diet is really a high fat diet. Excess sugar is stored as fat and ingested fat is also stored.
This is worth repeating. If the diet is made up of grains and starches there is a lot of sugar in the bloodstream and because of its toxicity glucose will always be metabolised in preference to fat which is the alternative energy source for the cells.
Unlike glucose, fat is non toxic and will not be metabolised until glucose and insulin have left the bloodstream. This is why it will take about 20 minutes of exercise until the body starts to burn fat and also why drinking energy drinks or munching on snacks will ensure that fat is not burnt, just stored.
Back to low carb flu. Cutting out or reducing the sugar available to cells means that the switch to fat burning has to occur but once the glucose is ushered from the bloodstream, the brain sensing a low sugar situation calls for more carby foods, hunger strikes but being on a low carb regime means the carbs are not available. It is this sustained period of adjustment which delivers the really ill, low energy situation that few wish to repeat.
There are benefits to getting through the low carb flu. Fat burning is constant, evening out energy levels keeping blood sugar under control. The need to constantly eat, nibble or snack is also removed and missing a meal is not a calamity – you eat when you are hungry and you recognise the feeling of real hunger. Finally, improved energy levels can lead to spontaneous exercise. Running without pain, just for the pleasure – great.