Low-calorie diets for prolonged periods can have harmful effects on metabolism, reproductive hormones, performance, and loss of lean muscle. Most anti-aging diets recommend protein restriction, but this results in the loss of muscle. Resistance exercise is the most effective form of exercise for retaining muscle while losing body fat while dieting.
SUMMARY OF LOW PROTEIN ANTI AGING DIETS DIETS
- Low protein anti aging diets can lead to muscle loss.
- Reduced calorie diets for prolonged periods can have harmful effects on metabolism, reproductive hormones, performance, and loss of lean muscle.
- Protein restriction on low protein anti aging diets results in reduced sex drive.
- Resistance exercise is the most effective form of exercise for retaining muscle while losing body fat while dieting.
Anti-aging diets are nothing new. Ponce De Leon sailed to find the Fountain of Youth, a mystical spring that restored the youth to anyone who drank from the water. I once visited the Fountain of Youth Memorial in St. Augustine, Florida.
Interestingly, the tour guide said that Ponce de Leon did think he discovered the fountain of youth when he arrived in Florida because the native Americans looked more youthful than his soldiers.
The tour guide explained that the creek was a good source of mineral water. Ponce men all had nutrient and mineral deficiencies that had prematurely aged them. Fast forward to 2023, and people are still looking for the fountain of youth. There are a few things that all anti-aging diets have in common:
- Reduce body fat by consuming a low-calorie diet.
- Decrease protein to increase longevity.
- Increase consumption of fruits and vegetables.
- Do more aerobic exercise.
The three main fallacies I want to address are low protein diets, the best way to reduce body fat and build muscle, and which forms of exercise are best (i.e., cardio vs. weights).
Low Protein Anti Aging Diets AND mTOR
The prevailing dogma of following a low-protein diet is to reduce mTOR. (Papadopoli et al., 2019) mTOR is a master trigger for cellular growth. mTOR activates nutrient-sensing pathways that activate IGF-1, which regulates cell growth. If you slow down cell growth, you can slow down the again process. Certain amino acids increase mTOR activity, such as leucine.
Animal studies have shown that drugs that block mTOR signaling increase longevity. (Weichhart, 2018) Studies have shown that increased mTOR production is associated with cancer, insulin resistance, osteoporosis, and other diseases. (Zou et al., 2020)
It sounds like blocking mTOR is something we need to do! A few things that block mTOR are a low-protein diet, fasting, and calorie restriction. (Kitada et al., 2019; Xie et al., 2022) However, there are benefits to a calorie-restricted diet, but if the calorie restriction is large, there are negative physiological effects.
NEGATIVE EFFECTS OF PROLONGED CALORIE RESTRICTION
There is a condition often experienced by endurance athletes, gymnasts, and other athletes that need to cut calories to stay in a weight class constantly, or they are just burning too many calories thru exercise called low energy availability.
Low energy availability is the result of chronic restriction of calories. Side effects of low energy availability include osteoporosis, loss of muscle mass, reduced hormone production, a compromised immune system, and decreased strength and performance. (Wasserfurth et al., 2020)
These are similar symptoms many people experience following a severely calorie-restricted anti-aging diet. (Flanagan et al., 2020) What is the purpose of living longer if you can’t have a fully functional life?
Low Protein Anti Aging Diets SIDE EFFECTS
A number of studies have shown that a low-protein diet can increase longevity. A very important point is that most of the research on anti-aging has been conducted on fruit flies, rats, mice, etc. (Le Couteur et al.) However, these don’t necessarily apply to humans.
Blocking mTOR also affects muscle function. Studies have shown that blocking mTOR can inhibit muscle growth. (Yoon, 2017) Research has shown that following a low-protein diet for weight loss is worse for maintaining lean muscle mass than high-protein diets.(Bopp et al., 2008; Carbone & Pasiakos, 2019)
IS LOSING MUSCLE GOING TO EXTEND YOUR LIFE?
Is the price of longevity by following a low-calorie, low-protein diet supersede the cost of losing muscle? It’s not! A recent article on Evidence Based Muscle discusses losing muscle mass was associated with an increased risk of death.
Large-scale studies have shown that lower protein intake is associated with muscle loss. (Huh & Son, 2022) Most people who suffer from severe kidney disease are recommended to consume low-protein diets; however, they experience muscle loss. (Hsu et al., 2021)
The amount of protein to maintain muscle mass varies but organizations. The International Society for Sports Nutrition recommends that the athletic population consume 1.6-2.4 g/kg/bw or .8 – 1.1 grams per pound of body weight to retain muscle while dieting. (Aragon et al., 2017)
MUSCLE IS IMPORTANT FOR HEALTHY AGING
Another important point is that no long-term studies suggest that a prolonged severe calorie-restricted diet will extend the lifespan in humans. I am not saying that calorie restriction and losing body fat are not important for prolonging lifespan. Obesity and diabetes from excess fat are the leading causes of death worldwide.
At least 2.8 million adults die annually because of being overweight or obese. 44% of the deaths are related to diabetes, 23% are because of ischemic heart disease, and between 7% and 41% of certain cancers are attributable to overweight and obesity.(Abdelaal et al., 2017)
A huge obstacle to anti-aging diets is getting people to adhere to the diet for long periods of time. The research shows that 80% of people who lose weight by following a diet will regain the weight within 5 years, and half will regain the weight loss in 2 years. (Hall & Kahan, 2018)
WHAT IS THE BEST WAY TO GAIN MUSCLE WHILE LOSING FAT
A tiered calorie restriction program with exercise is the best way to lose body fat while maintaining muscle. The research is fairly conclusive that anytime you go on a diet, if you don’t exercise, you will lose muscle, whereas exercise is better for retaining muscle. (Wu et al., 2009)
Traditionally, aerobic exercise has been advised for weight loss. Aerobic exercise can result in fat loss while dieting but has little effect on maintaining muscle. Resistance exercise must be emphasized while dieting as it is more important for retaining muscle and losing body fat.
I mentioned earlier that diabetes is a major contributor to early death. Diabetes results in impaired glucose uptake in muscle resulting in insulin resistance and increased risk of cardiovascular disease. A loss in body fat can result in lower blood sugar levels and increased insulin sensitivity, lowering the risk of diabetes.
Strength training can improve glucose control and insulin sensitivity, independent of weight loss. (Jiahao et al., 2021) Studies have shown that resistance exercise is equally effective as aerobic exercise for improving blood glucose levels. (Nery et al., 2017)
IS CARDIO NECESSARY FOR FAT LOSS?
Weight lifting vs. cardio for fat loss is a huge debate. Both are important, but if I had to choose one, it would be strength training. As written previously, you can follow a calorie-restricted diet, not do any cardio, and still lose weight and maintain muscle.
A study in obese men compared dieting, dieting plus cardio, and dieting plus resistance exercise for fat loss and muscle gain. The study found that dieting plus resistance exercise was more effective for losing body fat and gaining muscle. (Clark, 2015)
This is not to say that aerobic exercise is not important, but rather re-emphasizing that resistance exercise should be the main emphasis with cardio in lesser amounts performed. Why? Resistance exercise is more effective for maintaining muscle mass while dieting than cardio. (Cava et al., 2017)
Types of Cardio
Now that you know, the bulk of your training should focus on resistance exercises for optimal changes in body composition. Is there a best form of cardio for fat loss? There are two types of cardio.
Low-intensity, steady-state cardio (LISS): LISS is usually performed for 30-60 minutes at an exercise intensity of 60% of your maximal heart rate. Steady-state cardio for fat loss is often recommended because you burn more fat, but read this article to see why this does not always relate to fat loss.
High-Intensity interval training (HIIT): HIIT (high-intensity interval training) is a form of interval training that involves short bursts of intense exercise with periods lower intensity exercise while recovering between sessions. The typical HIIT workout lasts between 3-20 minutes.
You can do either form of cardio and lose fat. The research has shown that HIIT and LISS are equally effective for fat loss. It’s a matter of preference; if you want to get in and out of the gym faster, HIIT is the best choice. LISS is a better option for those who don’t like high-intensity exercise but still want to burn calories.
There are no doubt benefits to consuming fewer calories per day to lose body fat and achieve a healthy body fat; however, there is a point of diminishing returns in which you start doing more damage than good. Low protein anti aging diets are not optimal for improving longevity. If calorie restriction starts resulting in the loss of lean muscle for health, there are clear metabolic consequences. Loss of muscle mass can accelerate signs of aging.
The current anti-aging recommendation should place greater emphasis on resistance exercise and consuming more protein to circumvent the loss of muscle. Losing muscle has devasting effects not only on your performance and health. Anti-aging should emphasize the importance of building/maintaining muscle as we age to maximize longevity.
Abdelaal, M., le Roux, C. W., & Docherty, N. G. (2017). Morbidity and mortality associated with obesity. Annals of translational medicine, 5(7), 161-161. https://doi.org/10.21037/atm.2017.03.107
Aragon, A. A., Schoenfeld, B. J., Wildman, R., Kleiner, S., VanDusseldorp, T., Taylor, L., Earnest, C. P., Arciero, P. J., Wilborn, C., Kalman, D. S., Stout, J. R., Willoughby, D. S., Campbell, B., Arent, S. M., Bannock, L., Smith-Ryan, A. E., & Antonio, J. (2017). International society of sports nutrition position stand: diets and body composition. J Int Soc Sports Nutr, 14, 16. https://doi.org/10.1186/s12970-017-0174-y
Bopp, M. J., Houston, D. K., Lenchik, L., Easter, L., Kritchevsky, S. B., & Nicklas, B. J. (2008). Lean mass loss is associated with low protein intake during dietary-induced weight loss in postmenopausal women. Journal of the American Dietetic Association, 108(7), 1216-1220. https://doi.org/10.1016/j.jada.2008.04.017
Carbone, J. W., & Pasiakos, S. M. (2019). Dietary Protein and Muscle Mass: Translating Science to Application and Health Benefit. Nutrients, 11(5), 1136. https://doi.org/10.3390/nu11051136
Cava, E., Yeat, N. C., & Mittendorfer, B. (2017). Preserving Healthy Muscle during Weight Loss. Advances in nutrition (Bethesda, Md.), 8(3), 511-519. https://doi.org/10.3945/an.116.014506
Clark, J. E. (2015). Diet, exercise or diet with exercise: comparing the effectiveness of treatment options for weight-loss and changes in fitness for adults (18-65 years old) who are overfat, or obese; systematic review and meta-analysis. Journal of diabetes and metabolic disorders, 14, 31-31. https://doi.org/10.1186/s40200-015-0154-1
Flanagan, E. W., Most, J., Mey, J. T., & Redman, L. M. (2020). Calorie Restriction and Aging in Humans. Annual Review of Nutrition, 40, 105-133. https://doi.org/10.1146/annurev-nutr-122319-034601
Hall, K. D., & Kahan, S. (2018). Maintenance of Lost Weight and Long-Term Management of Obesity. The Medical clinics of North America, 102(1), 183-197. https://doi.org/10.1016/j.mcna.2017.08.012
Hsu, H.-J., Yen, C.-H., Wu, I. W., Liu, M.-H., Cheng, H.-Y., Lin, Y.-T., Lee, C.-C., Hsu, K.-H., Sun, C.-Y., Chen, C.-Y., & Wang, C.-H. (2021). The association between low protein diet and body composition, muscle function, inflammation, and amino acid-based metabolic profile in chronic kidney disease stage 3–5 patients. Clinical Nutrition ESPEN, 46, 405-415. https://doi.org/https://doi.org/10.1016/j.clnesp.2021.08.037
Huh, Y., & Son, K. Y. (2022). Association between total protein intake and low muscle mass in Korean adults. BMC Geriatrics, 22(1), 319. https://doi.org/10.1186/s12877-022-03019-1
Jiahao, L., Jiajin, L., & Yifan, L. (2021). Effects of resistance training on insulin sensitivity in the elderly: A meta-analysis of randomized controlled trials. J Exerc Sci Fit, 19(4), 241-251. https://doi.org/10.1016/j.jesf.2021.08.002
Kitada, M., Ogura, Y., Monno, I., & Koya, D. (2019). The impact of dietary protein intake on longevity and metabolic health. EBioMedicine, 43, 632-640. https://doi.org/10.1016/j.ebiom.2019.04.005
Le Couteur, D. G., Raubenheimer, D., Solon-Biet, S., de Cabo, R., & Simpson, S. J. Does diet influence aging? Evidence from animal studies. Journal of Internal Medicine, n/a(n/a). https://doi.org/https://doi.org/10.1111/joim.13530
Nery, C., Moraes, S. R. A., Novaes, K. A., Bezerra, M. A., Silveira, P. V. C., & Lemos, A. (2017). Effectiveness of resistance exercise compared to aerobic exercise without insulin therapy in patients with type 2 diabetes mellitus: a meta-analysis. Braz J Phys Ther, 21(6), 400-415. https://doi.org/10.1016/j.bjpt.2017.06.004
Papadopoli, D., Boulay, K., Kazak, L., Pollak, M., Mallette, F., Topisirovic, I., & Hulea, L. (2019). mTOR as a central regulator of lifespan and aging. F1000Research, 8, F1000 Faculty Rev-1998. https://doi.org/10.12688/f1000research.17196.1
Wasserfurth, P., Palmowski, J., Hahn, A., & Krüger, K. (2020). Reasons for and Consequences of Low Energy Availability in Female and Male Athletes: Social Environment, Adaptations, and Prevention. Sports Medicine – Open, 6(1), 44. https://doi.org/10.1186/s40798-020-00275-6
Weichhart, T. (2018). mTOR as Regulator of Lifespan, Aging, and Cellular Senescence: A Mini-Review. Gerontology, 64(2), 127-134. https://doi.org/10.1159/000484629
Wu, T., Gao, X., Chen, M., & van Dam, R. M. (2009). Long-term effectiveness of diet-plus-exercise interventions vs. diet-only interventions for weight loss: a meta-analysis. Obes Rev, 10(3), 313-323. https://doi.org/10.1111/j.1467-789X.2008.00547.x
Xie, D., Huang, J., Zhang, Q., Zhao, S., Xue, H., Yu, Q.-Q., Sun, Z., Li, J., Yang, X., Shao, M., Pang, D., & Jiang, P. (2022). Comprehensive evaluation of caloric restriction-induced changes in the metabolome profile of mice. Nutrition & Metabolism, 19(1), 41. https://doi.org/10.1186/s12986-022-00674-4
Yoon, M.-S. (2017). mTOR as a Key Regulator in Maintaining Skeletal Muscle Mass. Frontiers in Physiology, 8, 788-788. https://doi.org/10.3389/fphys.2017.00788
Zou, Z., Tao, T., Li, H., & Zhu, X. (2020). mTOR signaling pathway and mTOR inhibitors in cancer: progress and challenges. Cell & Bioscience, 10(1), 31. https://doi.org/10.1186/s13578-020-00396-1