Purpose of Review <p>This review aims to comprehensively evaluate the effects of plant-based diets (PBDs) on energy metabolism, with particular attention to their potential impacts on total energy expenditure (TEE) through basal metabolic rate (BMR), the thermic effect of food (TEF), and physical activity (PA), as well as the underlying physiological and biochemical mechanisms. Additionally, this work aims to explore the scope of changes in energy metabolism in relation to the effects of PBDs on metabolic functions, and to examine how these changes reflect on overall metabolic balance.</p> Recent Findings <p>Plant-based diets appear to influence energy metabolism through various mechanisms, including increased dietary fiber intake, higher consumption of plant-based fats, greater intake of polyphenols and antioxidants, and reduced consumption of energy and animal-based proteins. Moreover, PBDs may impact energy metabolism by promoting weight loss, reducing lean and fat mass, and altering body composition. Although there is some evidence suggesting that PBDs may affect energy metabolism and metabolic functions, the existing research is limited and inconsistent.</p> Summary <p>PBDs may affect energy metabolism through their dietary pattern and content. The impact of PBDs on metabolic functions through their effect on energy metabolism is also notable. Further research is required to investigate the impact of plant-based diets on energy metabolism and to clarify the relationship between changes in energy metabolism and metabolic functions.</p>