Why the Scales Won't Tell You the Whole Story

There is a lot of scientific evidence to support the relationship between increasing weight and reductions in fertility, but as we also know improvements in fertility can been realised just a few months after adopting a more active lifestyle, even without weight loss.

Your weight is made up of body fat and fat free mass, which includes your muscle and bone. It is the proportion of each of these that is important in influencing your health and fertility. Muscle is metabolically active tissue which means that if a higher proportion of your body weight is made up of muscle, your metabolic rate is higher, burning more calories. You also have the benefit of improved glucose regulation, improved mitochondrial biogenesis (making new components of the energy storehouses in our cells), strength for everyday activities, and improved bone and tendon health.

The findings from a recent study published in Clinical Nutrition are a great illustration of why resistance training should be a component of your regular exercise routine rather than focusing on a number on the scales (1). In the study, overweight men and women were allocated to a very low energy diet for three months with some walking exercise, or the same very low energy diet and walking with resistance training 3 x week.

​Weight loss in the group that did not resistance train was 19.4kg while the resistance training group lost 15.8kg. Now, if you were just looking a number of the scales you would assume that the resistance training was not as beneficial. But wait- there is more to the story!

Using techniques that can differentiate between fat mass and lean mass, the researchers showed that the group that did no resistance training lost 4.6kg of lean mass (muscle). That is almost 5kg of metabolically active tissue! This translated to a reduction in resting metabolism, meaning that their metabolic rate was reduced. This is important to note as when a significant amount of weight is lost, metabolic rate is often reduced which reflects a slower metabolism, which can make it difficult to lose more weight.

So what happened in the resistance training group? The group that resistance trained three times a week lost no muscle mass and their metabolic rate stayed the same, unlike the other group who experienced a reduction in resting energy expenditure. The scales alone as you can see did not tell the whole story! Resistance training was superior for weight-loss composition by preserving lean mass, and still enabling the loss of body fat.
 
Ideal body composition is important for fertility, regardless of your body weight. Have you got the optimal resistance training prescription to enhance your fertility?

Reference

1. Jo, E., Worts, P.R., Elam, M.L., Brown, A.F., Khamoui, A.V., Kim, D.H., Yeh, M.C., Ormsbee, M.J., Prado, C.M., Cain, A., Snyder, K., andKim, J.S. (2017). Resistance training during a 12-week protein supplemented VLCD treatment enhances weight-loss outcomes in obese patients. Clin Nutr.