A popular and ever present New Year's resolution is to get “in shape”. The intent behind this is well suited and tends to lead to some sort of action. However, the problem with this arbitrary goal is that it lacks specificity or really any formal definition. The root of the issue is that “in shape” is very specific to one's bigger goals or health needs e.g. if I want to run a marathon in 2021 it lends to a different type of being “in shape” than it does if I want to compete in a bodybuilding competition. Likewise, if I am underweight and need to gain muscle and fat mass for the betterment of my health then my definition of “in shape” is different from someone who is obese and needs to lose 40lbs of fat to get “in shape” and avoid the onset of cardiovascular disease.
Fortunately, there is a measurement that allows us to obtain a formal definition of “in shape” and that is body fat percentage or the amount of fat on our body relative to our overall body weight. This number is directly correlated to not only our literal body shape but also numerous health indicators such as waist circumference, blood lipid profile, insulin sensitivity, and blood pressure. This number should not be confused with Body Mass Index (BMI) which is misleading (and outdated) as it is simply a measurement of weight to height (kg/m2) and does not take into consideration what your body is actually composed of, wherein lies the aforementioned benefits.
Despite what your goals may be for the new year (clothes fitting better, running a marathon, competing in a physique contest, playing with the grandkids, etc) testing and consistently tracking your body composition is an essential, health protective habit that will give you a more global picture of your body and only benefit you in the pursuit of your goals.