In preparation for a fitness competition, a very low body fat percentage can significantly disrupt women’s hormonal balance. Research from Finland shows that after 4 months of recovery, this can largely normalize.
Low Body Fat Percentage and Menstruation
Participants in fitness and bodybuilding competitions know that they cannot maintain the shape they bring to the stage. The body fat percentage displayed on stage is simply unhealthy low (if you want a chance) and only temporarily desirable.
For women, this low body fat percentage can disrupt hormonal balance significantly. I often hear from participants that, for example, their menstruation stops because of this.
Naturally, this fuels the criticism of skeptics who already do not understand why you would subject yourself to this. So, I can imagine that this is information that participants don’t always like to share with concerned friends and family.
From today, however, the ladies in bikini fitness, figure, and physique have their answer ready for the critics. Three words to silence them: Hulmi et al.
Referring to the Finnish researchers from the University of Jyväskylä and their findings [1].
The research confirms the thought with which many justify their decision to participate in competitions: “The low body fat percentage on stage is unhealthy. But this is temporary, and afterwards, you work on recovery.”
In conclusion, a fitness diet in healthy young females accomplished by restricting carbohydrate ingestion and increasing aerobic exercise while maintaining high levels of protein intake and resistance exercise can be carried out without major decreases in lean mass/muscle size. Therefore, the diet almost exclusively decreased body fat and altered serum hormones, but most of those values recovered within 3–4 months with the increase in energy intake and decrease in high level of aerobic exercise. However, in some females this time period may not have been long enough for a full recovery (e.g., free T3 and testosterone hormones).
Nice Test Group
Juha Hulmi and his colleagues specifically focused their research on women participating in competitions. 27 Finnish women preparing for a fitness competition were followed for four months. 23 women who maintained weight served as a control group.
All of the diet participants were IFBB amateur fitness competitors aiming to lose fat, but maintain their muscle mass in a sport that is tested for prohibited performance enhancing drugs. Out of these participants, 17 were bikini fitness and 9 body fitness competitors and 1 was a fitness competitor.
In the competition group, women lost an average of 12 kilograms and decreased their body fat percentage by 35 to 50 percent. There was also the expected decrease in muscle mass. This remained the same in the control group.
Effect of Low Body Fat Percentage on Hormonal Balance
The researchers were particularly interested in the hormonal balance in response to the diet and training regimen (fig. right).
The hormonal system was altered during the diet with decreased serum concentrations of leptin, triiodothyronine (T3), testosterone (P < 0.001), and estradiol (P < 0.01) coinciding with an increased incidence of menstrual irregularities (P < 0.05). Body weight and all hormones except T3 and testosterone returned to baseline during a 3–4 month recovery period including increased energy intake and decreased levels aerobic exercise.
As you can see, not all values have fully recovered after 3-4 months. The researchers also note that the 3 to 4 months may not be enough in some cases.
Incidentally, in the entire study, the possible use of testosterone and T3 (never to be excluded in this target group) is not mentioned anywhere. It is only mentioned that they participate in competitions where this is not allowed. Of course, this does not rule out usage, and its potential influence on the study.
Nevertheless, you seem to have some nice graphs to use if someone says that you permanently disrupt your hormonal balance with a competition shape. I deliberately choose this word to emphasize the temporary aspect of such a form.
Effect of Low Body Fat Percentage on Menstruation
What were the effects of dieting and recovery on the menstrual cycle? The researchers don’t provide concise summaries, so I’ll present it as succinctly as possible in a table. “During diet” can also mean measured during the prep or just before the competition.
The researchers mention these numbers but don’t elaborate further. They are not very clear either.
| Missed Period | Competition Group | Control Group |
| Before Diet | 11.10% | 4.30% |
| During Diet | 44% | 22% |
| After Recovery | 28% | 14% |
| Irregular Bleeding | Competition Group | Control Group |
| Before Diet | 37% | 30% |
| During Diet | 63% | 30% |
| After Recovery | Not mentioned | Not mentioned |
We see a clear difference between the competition group and control group. In the competition group, there are more cases of missed periods or irregular bleeding. We also see that these numbers increase in the competition group during the diet. All in line with expectations.
However, we can also see that the number of missed periods after the recovery period has decreased, but is still very high compared to the starting value (28% compared to 11.1%). The researchers do not mention the number of irregular bleedings after recovery. However, the most striking figure is the almost quintupling of the number of missed periods in the control group halfway through the study. This group was not dieting. “During diet” refers to the period when the other group was dieting. If the number of cases in that group can increase from 4.3% to 22% without explanation, what does that say about the other (smaller) results?
Participants were not excluded for the use of contraceptive pills, which complicates matters. This could also have had an influence.
So, there may be too many factors to measure this effect accurately. For now, we have to hope that a restored hormonal balance should limit any menstrual problems caused by dieting over time.
Conclusion
On the one hand, it is great that we have been able to observe “the fitness athlete in her natural environment.” This target group is relevant for the many participants in fitness and bodybuilding competitions. So far, the effects of a low body fat percentage on hormones have mainly been measured in women with anorexia [2,3]. This is not comparable to women who ensure sufficient fats and proteins and retain as much muscle mass as possible. However, using these competition athletes also meant that various variables that could have been influential could not be controlled. After all, they maintained their own nutrition and training regimes, which differed among them.
A similar, but larger study that succeeds better in this and lasts longer could provide more insight. For example, is there full recovery in all areas after 6 months? What should recovery entail in terms of the amount of food and composition of macros? The Finnish researchers were probably already pleased that they could follow this number of ladies. And again, it is nice to see researchers specifically targeting the fitness community.
Finally: of course, you have to put that recovery into practice. In this study, we cannot see the individual recovery periods. However, there is always a risk group consisting of people who have significant difficulties mentally recovering. People who, rightly or wrongly, feel the need to be in shape all year round. Maybe less dry than on stage, but not sufficiently recovered to restore hormonal changes.
This research at least shows that there is a good chance that the hormonal balance of women can be restored in the long term, after 4 months or longer.
References
- journal.frontiersin.org/article/10.3389/fphys.2016.00689/full
- Tolle, V., Kadem, M., Bluet-Pajot, M. T., Frere, D., Foulon, C., Bossu, C., et al. (2003). Balance in ghrelin and leptin plasma levels in anorexia nervosa patients and constitutionally thin women. J. Clin. Endocrinol. Metab. 88, 109–116. doi: 10.1210/jc.2002-020645
- Miller, K. K., Lawson, E. A., Mathur, V., Wexler, T. L., Meenaghan, E., Misra, M., et al. (2007). Androgens in women with anorexia nervosa and normal-weight women with hypothalamic amenorrhea. J. Clin. Endocrinol. Metab. 92, 1334–1339. doi: 10.1210/jc.2006-2501
