7.  Side effects
The ketogenic diet can be tough on the mind and body. Physical responses, aside from weight loss, can include headaches, lethargy, sleepiness and even sometimes nausea.

Some also experience cognitive decline, i.e. feeling foggy, confused and flat. Some peolple experience mood swings. A combo of these symptoms has been described as the 'keto flu'. Not everyone experiences all these things, but for those who do the best option may be to temporarily increase your carb intake then decrease back to ketogenic amounts in stages. More stubborn dieters might consider upping their calorie consumption or – and how effective this is will depend on what is causing your symptoms – increasing their fluid and electrolyte intake. If problems persist, please seek professional advice from your GP or nutritionist.