While estimating BF% is important for many reasons, at least one of those is for you to determine what dieting category you are in. This is a delineation Lyle Mcdonald has used for many years and is based around the fact that a woman's physiology is changing to one degree or another based on her current BF%. I won't detail those here but those physiological changes impact on many practical aspects such as how much protein she might need while dieting, her relative risk of menstrual cycle dysfunction, how rapidly she will be able to lose weight or fat, her relative risk of muscle loss and others. When we look at the research relating to women's body fat issues, it will be important to recognise what category the subjects being studied are in. I've presented the categorisation system using the BF% methods outlined in the last blog.
While I have presented the table with rather discrete cut off points, please realise that this is a continuum. The cutoff points are based on underlying physiology but it's not as if physiology changes completely from one category to the next. A woman at 35% body fat is far closer to a Category 2 female physiologically than a woman at 45%. Similarly, a Category 2 dieter at 25% is essentially the same as a Category 1 dieter. But some sort of delineation is required to make the system work and I'll only suggest that women at the very low end of one Category should consider themselves in the next lower category in terms of the rest of this blog. So a woman at 35% body fat should consider herself in Category 2 in terms of her diet set up, etc.
Some Category Comments
Before looking at some last practical issues, I want to make some brief comments about the Categories above and who might typically be found within them. In general, the Category 1 female tend to be involved in some degree of training. They could be in one of the physique sports, a performance sport or be what I will call a serious trainee (possibly workout out intensely 5-6 times per week but not competing). In many cases, either for performance, competition or appearance, these women will want to lose some amount of body fat As frequently they may want to gain muscle. The physique athlete may wish to bring up weak body parts and many performance sports benefit from increased muscle mass. I'd note that there can be a Category 1 female who is not active or training. They frequently are genetically lean although they still want to lose weight. Weight gain is a rare but very occasional goal.
Category 2 tends to span the broadest range of possible situations since it matches up with relatively average BF% for women to begin with. Athletes may be in this group as many sports do not require extreme leanness, many recreationally exercising women may also be in this group. It's possible for a physique athlete who let their body fat get away from them in the off-season to be here although that can cause a lot of problems when it's time to diet down for a contest. The serious trainee might fall here if here diet isn't set up correctly such that, despite all of the training, she is not losing body fat or maintaining a lower body fat effectively . It's just as likely for women to be in Category 2 who are sedentary or only minimally active. Fat loss is likely to be the primary goal in this group.
In general, Category 3 women are the least likely to be involved in any sort of training program or sports although there are certainly exceptions. Overall, it is far more likely for the Category 3 women to be relatively sedentary. In this case, fat/weight loss and/or improving health and fertility is likely to be the exclusive goal.