Foods that are permitted on the Atkins diet include fat and protein from butter, poultry, vegetable oils, fish, eggs and red meat, says WebMD. Foods that aren't permitted on the Atkins diet include bread, pasta, grains, starchy vegetables, beans and nuts. Caffeine and alcohol are also prohibited.
The Atkins diet drastically cuts back on carbohydrates to force the body to use fat for fuel, notes WebMD. As fat stores are being used up, the body releases ketones, a by-product that provides energy. Individuals who have severe kidney disease should not follow the Atkins diet.
After the initial stage of the Atkins diet, people are allowed to eat more vegetables, legumes, nuts, berries, wine, seeds and whole grains, says WebMD. Depending on individual goals and needs, some dieters may be allowed to eat more carbohydrates than others.
People following the Atkins diet sometimes have a hard time ingesting enough magnesium, calcium and potassium, as stated by WebMD. Foods allowed on the diet can be limited, meaning that a person may have to eliminate a number of his favorite foods. For optimum weight loss, people on the Atkins diet are encouraged to engage in at least a half hour of exercise several days a week.