There are various reasons for not losing weight while on a low-carb diet, like eating too many low carb treats in a day, snacking on too many fruits, not exercising enough, eating too much or too less proteins, too many cheat meals per week, too much fat consumption, stress, hormonal imbalance, and not getting enough sleep. Record what you are eating, your exercise routine, and your daily activities for three days. You may show this to your trainer or doctor to know if you are strictly following the keto diet plan.