Core Viewpoint - The article discusses a recent study that reveals the role of a metabolite called Lac-Phe, produced during exercise, in suppressing appetite and aiding weight control, thereby enhancing understanding of the relationship between exercise and appetite regulation [6][10][12]. Group 1: Research Findings - A study published in *Nature* by researchers from Stanford University and Baylor College of Medicine identified Lac-Phe, a small molecule formed during exercise, which significantly reduces food intake and helps control weight [7][10]. - High doses of Lac-Phe can reduce food intake by nearly 50% within 12 hours in mice on a high-fat diet, without affecting their activity or energy expenditure [12]. - The study found that Lac-Phe levels significantly increase after exercise in both horses and humans, with the highest levels observed after sprinting, followed by resistance training and endurance training [13]. Group 2: Implications for Health - Regular exercise has been shown to aid in weight loss, appetite regulation, and metabolic improvement, particularly for overweight and obese individuals [10]. - The research suggests that understanding the molecular mechanisms behind exercise-induced health benefits could lead to new drug developments for individuals unable to exercise sufficiently, such as the elderly or frail patients [10][16]. - The findings reinforce the notion that exercise acts as a "medicine," promoting the production of Lac-Phe to suppress appetite and control weight, which is crucial in combating obesity-related health risks [16].

Core Viewpoint - The article discusses a recent study that reveals the role of a metabolite called Lac-Phe, produced during exercise, in suppressing appetite and aiding weight control, thereby enhancing understanding of the relationship between exercise and appetite regulation [6][10][12]. Summary by Sections Exercise and Metabolism - Exercise has been proven to effectively prevent obesity and related chronic diseases by increasing the body's energy demand and promoting calorie burning. However, many long-term benefits of exercise on physiological functions and metabolic health remain unexplored [6]. Research Findings - A study published in *Nature* by researchers from Stanford University and Baylor College of Medicine identified Lac-Phe, a small molecule synthesized from lactate and phenylalanine, which significantly reduces food intake during exercise [7][10]. - High doses of Lac-Phe can reduce food intake by nearly half within 12 hours in mice on a high-fat diet, without affecting their activity or energy expenditure. Continuous injection of Lac-Phe over ten days led to reduced food intake, weight loss (primarily fat loss), and improved glucose tolerance [12]. Mechanism of Action - The key enzyme required for Lac-Phe synthesis is CNDP2. Mice lacking this enzyme showed less pronounced weight loss effects after exercise compared to the control group. The appetite-suppressing effect of Lac-Phe appears primarily after exercise and is particularly effective in mice that gained weight from a high-fat diet [15]. Broader Implications - The study suggests that the production of Lac-Phe post-exercise is an ancient and conserved physiological mechanism present in various animals and humans, playing a role in regulating food intake [16]. - The researchers aim to further explore the specific mechanisms and downstream pathways of Lac-Phe in the body, especially in the brain, with the hope of developing new interventions for health improvement and treatment [16].