Most diets are foreign to our bodies, and in the quest to reduce body fat, we need to remember that long-term dieting together with weight training can have negative consequences. Body fat reduction can, for example, disrupt hormonal balances in women.
A recently published study on female athletes dieting 20 weeks for competition evaluated lean body mass, body fat %, hormone levels (leptin, T3, estradiol, testosterone, cortisol), and menstrual cycle changes. Decreased satiety hormone (leptin), thyroid hormone (T3), and estrogen levels were observed. Cortisol was unaffected. Other studies show similar results. After competition recovery, hormone levels returned to normal levels. However, it took 5-7 months before the women got their periods again! Apart from the above, the hormonal changes may also mean risk of heart disease and a weakened skeleton.
For short term women dieters, these changes are likely not harmful. However, for competing athletes who diet regularly, the risks are very real and something that coaches should keep in mind.
- Juha J.Hulmi, VilleIsola, MariannaSuonpää, NeeaJ.Järvinen, MarjaKokkonen,Annika Wennerström, KaiNyman, MarkusPerola, JuhaP.Ahtiainen and Keijo Häkkinen The Effects of Intensive Weight Reduction on Body Composition and Serum Hormones in Female Fitness Competitors Frontiers, 7, 689. doi:10.3389/fphys.2016.00689
- Tanya M. Halliday, Jeremy P. Loenneke and Brenda M. Davy Dietary Intake, Body Composition, and Menstrual Cycle Changes during Competition Preparation and Recovery in a Drug-Free Figure Competitor: A Case Study Nutrients, 2016