Does Metabolism Drop WITH Age?

1. What You Hear
  • Metabolism sharply drops at a certain age causing unavoidable weight gain.
  • Everyone’s metabolism slows down equally with age.
  • Weight gain after middle age is solely due to metabolism decline.
  • Exercise cannot offset metabolism decline with aging.
2. What The Science Says
  • Resting metabolic rate (RMR) declines gradually with age, about 1-2% per decade after young adulthood, and accelerates after 60 years old.
  • Decline in RMR is partly due to loss of lean muscle mass and reduction in organ mass.
  • Studies show the decrease in metabolism is modest after adjusting for body composition changes.
  • Lipid turnover in fat tissue slows with age, reducing fat breakdown independent of calorie intake or exercise.
  • Physical activity levels typically decrease with age, leading to a larger effect on total energy expenditure than metabolism alone.
3. What Actually Causes Weight Gain
  • Loss of skeletal muscle (sarcopenia) reduces energy needs, contributing to fat gain if diet is unchanged.
  • Reduced physical activity lowers energy expenditure and promotes fat accumulation.
  • Lipid turnover in fat cells decreases, leading to easier fat storage.
  • Hormonal changes (like menopause in women and testosterone decline in men) shift fat distribution and promote adiposity.
  • Poor sleep, chronic stress (increasing cortisol), and lifestyle factors also play significant roles in weight gain.
4. What You Should Probably Do 
  • Maintain or increase physical activity, especially resistance training to preserve muscle mass.
  • Prioritize a balanced diet with adequate protein to support metabolism and muscle.
  • Monitor and reduce stress, improve sleep quality to help regulate weight.
  • Adapt calorie intake to age-related changes but avoid unnecessary severe restrictions.
5. Where Everything You Read Above Came From
  • Palmer AK, Jensen MD. Metabolic changes in aging humans: current evidence and therapeutic strategies. J Clin Invest. 2022;132(16):e158273. DOI:10.1172/JCI158273.
  • Rizzo MR, et al. Basal metabolic rate and aging: threshold effect and mortality relationship. Front Endocrinol (Lausanne). 2022;13:790347. DOI:10.3389/fendo.2022.790347.
  • Arner P, et al. Lipid turnover in adipose tissue decreases during aging and predicts weight gain. Nat Med. 2019;25(7):1382-1388. DOI:10.1038/s41591-019-0535-4.
  • Hurtado MD, et al. Weight gain and body composition changes during midlife in women: A systematic review. Curr Opin Endocrinol Diabetes Obes. 2024;31(3):217-224. DOI:10.1097/MED.0000000000000707.
  • Schrack JA, et al. ‘IDEAL’ aging is associated with lower resting metabolic rate but greater survival. J Gerontol A Biol Sci Med Sci. 2014;69(10):1259-1267. DOI:10.1093/gerona/glt187.
  • San-Millán I, Brooks GA. Exercise and aging: differences in physiology and intervention effects. Med Sci Sports Exerc. 2018;50(4):589-599. DOI:10.1249/MSS.0000000000001467.
  • Faintuch J, et al. Changes in body composition with aging and their significance. J Clin Endocrinol Metab. 2023;108(3):e1576-e1584. DOI:10.1210/clinem/dgad004.
  • Wolfe RR. The underappreciated role of muscle in health and disease. Am J Clin Nutr. 2020;112(3):730-738. DOI:10.1093/ajcn/nqaa059.
  • Barnes PM, et al. Combined effect of diet and physical activity to mitigate muscle loss and metabolic decline with age. Nutrients. 2023;15(4):878. DOI:10.3390/nu15040878.
  • Leahy S, et al. Hormonal changes affecting body composition with aging: clinical implications. Clin Interv Aging. 2024;19:123-136. DOI:10.2147/CIA.S347784.