If you are starting your weight-loss transformation journey or have been trying everything without observing significant results, then you need to look at the status of internal health, i.e.
Microbiome has a very crucial role in weight-loss. "Bacteroidetes" are the anti-obesity bacteria whereas "Firmicutes" are obesity-inducers. The ratio of Bacteroids:Firmicutes indicates your propensity towards weight-loss & obesity.
If you are on special diet plan such as Keto, Paleo, Low-Carb etc, monitoring your biomarkers is very crucial as this type of diets are known to lower thyroid output, throw your hormonal profile off-balance and in-turn causes health conditions such as decreased libido, fertility, sexual function, hair-loss, muscle-loss etc. Regular monitoring is important if you are taking supplements.