The good, bad and ugly aspects of a ketogenic diet Severely restricting carbohydrates to less than 20 grams a day sets off a process called ketosis. It occurs when you don’t have enough sugar (glucose) for energy, so your body breaks down stored fat, causing ketones to build up in the body. Side effects from ketosis can include: nausea, headache, mental and physical fatigue, and bad breath. (That’s how you know it’s working!) The long-term health risks of a very low carbohydrate diet may outweigh the benefits. Some health experts believe that if you eat large and regular amounts of fat and protein from animal sources your risk of heart disease and certain cancers may increase. This is because of the increased methionine, homocysteine and resultant inflammation they can cause. https://www.naturefresh.co.za/Article/357