Caloric Deficit Guidelines 
15% below maintenance = very conservative deficit (playing it safe; slow fat loss but maximum retention muscle) 
20% below maintenance = conservative deficit (good starting point for people who have average body fat level) 
25% below maintenance = moderate deficit (good starting point for people with above average body fat) 
30% below maintenance = aggressive deficit (maximum fat loss – recommended for obese & time sensitive deadlines) 
35%+ below maintenance = very aggressive deficit (not recommended – high risk of metabolic slowdown & muscle loss) 
50%+ below maintenance = semi-starvation/starvation (potentially dangerous and unhealthy; extremely high risk)