In the first few days, as you switch from higher carbohydrates to a lower carbohydrate or ketogenic approach, you can feel lethargic, low energy and a bit irritable. In part, this is because the ready source of fuel (glucose) in blood stream is a lot lower, and your body hasn’t adapted to switching over to using fat as a fuel source. This changes over time, though, as you become more adapted to the ketogenic approach. In the beginning, it can be really helpful to have more water and sodium, as the lower carbohydrate approach drops our body’s ability to store water and electrolytes. Focusing on these two elements can help mitigate what people refer to as the ‘keto flu’. Some people do need to continue to focus on electrolytes in their lower carbohydrate lifestyle.