A diet that is degicient in carbohydrates can have an adverse effect on a person's health. When the bofy lacks a sufficient amount of carbohydrates it must then use its protein supplies for energy, a process called gluconeogenesis. This, however, results in a lack of necessary protein, and further health difficulties may occur. A lack of carbohydrates can also lead to ketosis, a build-up of ketones in the body thst causes fatigue, lethargy,and bad breath.