Calorie restriction influences metabolic rate by creating a negative energy balance, prompting the body to use stored fat for energy. However, excessive calorie restriction can lead to a decrease in basal metabolic rate (BMR) as the body adapts to conserve energy in response to perceived starvation. This metabolic slowdown can pose challenges for long-term weight loss. Maintaining a moderate caloric deficit while prioritizing nutrient-dense foods can help preserve lean muscle mass and support a healthier metabolism during weight management efforts.