Obesity is a primary risk factor for type 2 diabetes. The American Diabetes Association guidelines suggest that weight loss may decrease the risk of type 2 diabetes in prediabetic subjects. Weight loss of approximately 5% in overweight or obese diabetic patients may help manage blood glucose. Weight loss by regulating lifestyle interventions, including nutrition interventions, has been associated with a lower incidence of diabetes. Lifestyle intervention programs should be intensive and have frequent follow-up to achieve significant reductions in excess body weight and improve clinical indicators. A obese (Asian criteria) 49-year-old male with BMI(body mass index) 25.5 kg/㎡ received 4times lifestyle intervention including a nutrition therapy, from February to August 2018. Nutrition intervention to achieve weight loss focused on enhancing motivation and problem-solving skills to improve self-management ability. He was sufficiently motivated for weight management and was aware of the necessity of weight loss. He changed his bad eating habit. He tried to cut down on snacks, especially late-night snack and alcohol intake. Instead, he increased vegetable intake and stared exercise. Constant monitoring and encouragement through four visits within six months led to his behavior becoming a habit. As a result, this subject achieved 7.6% weight loss compared to initial weight and got an improved HbA1c level [6.4% → 6. 0% (6 month later) → 5. 7% (1 year later)]. This case suggests that weight loss (> 5%) achievable by the combination of reduction of calorie intake and lifestyle modification benefits overweight or obese adults with prediabetes