A ketogenic diet is when you cut out the carbs in your diet and increase the fat intake in your diet. In short, it is a very low-carb, high fat diet that is very similar to Atkins and other low-carb diets.
When you deprive your body of the carbs it goes into a metabolic state known as ketosis. Your brain and other organs need glucose as energy to function and depriving yourself of the carbs cause your liver to undergo ketogenesis. This ketogenesis occurs in the mitochondria of the liver cells. The fat gets converted into ketone bodies and during ketosis, your energy comes from these ketone bodies circulating in the blood
Your brain can function on ketone bodies in-fact ketone bodies provide more energy per gram for the brain vs glucose. So, we can see that with the keto diet your body will not be dependent on carbohydrates, it will burn down fat and your brain will function well but like every other diet keto diet has some downsides as well with the most significant of them coming during intense workouts which become a lot harder, this is because Glucose through glycolysis provides you the immediate energy that is needed during maximum intensity workouts and with ketogenic diet eliminating the intake of glucose and decreasing stored glycogen you can end up being fatigued soon. Glycogen is also needed for muscle growth in association with protein synthesis and with a ketogenic diet you can end up having a low muscle mass.
One down-side is keto flu as well, it is reported that many people who go for keto diet have experienced this keto-flu, a keto flu occurs during the ketogenic diet when your body starts being more dependent upon the ketone bodies for energy.it comprises of headache, fatigue, cough, nausea and digestive upset. One good thing is that this is self-resolving and resolves within 5 to 7 days.