Thinking of doing the abc diet, no what to do and all that, but what are the side effects?

Agree w Dr. McGee. With the Ana Boot Camp Diet would anticipate possible side effects like malnutrition, fatigue, overly rapid weight loss, dizziness, low energy level, loss of large % of muscle mass – including heart muscle, problems with sleep, electrolyte imbalances, cold sensitivity, depression, paranoia etc. It may also be the start of a pattern of unhealthy eating.
Dont advise AbC Diet. ANA boot camp or abc diet is extreme low calorie pro-anorexeia diet(ana = anorexia) normaly 50 days. Many health risks with this diet averages 300-500 cal/day with some 24 hr fasts. Extreme calorie and nutrient deprevation can cause abnormaly high ketones in the blood, muscle wasting, kidney and liver damage and electrolyte imbalance. It also slows metabolism leading to rebound weight gain.
Not recommended. All fad diets have side effects and often do not work long term. And may exacerbate other health problems. A good balance diet with moderating portions and regular exercise is the best way to diet.