A study was conducted to examine the relationship between percent body fat (%fat) and medical examination parameters. The subjects were 250 women aged 17 to 68 years, who neither drank nor smoked. The results obtained were as follows:
After controlling for the effects of age and maximal oxygen intake per kilogram body weight (VO₂max/wt), %fat showed a significant correlation with high-density lipoprotein cholesterol (HDL-C), total cholesterol/HDL-C ratio (TC/HDL-C), β-lipoprotein (β-L), glutamic oxaloacetic transaminase (GOT), glutamic pyruvic tansaminase (GPT), uric acid (UA), white blood cell count (WBC), red blood cell count (RBC), systolic blood pressure (SBP), and diastolic blood pressure (DBP) . Values of %fat calculated from each regression equation when HDL-C=38mg/dl, TC/HDL-C=4.9, β-L=500 mg/dl, GOT=41mu/ml, GPT=46 mu/ml, UA=5.7mg/dl, WBC=8500/mm3, RBC=520×104/mm3, SBP=159 mmHg, and DBP=94 mmHg were 32.2%, 31.9%, 30.8%, 35.4%, 36.4%, 31.8%, 30.7%, 35.0%, 33.8% and 32.6%, respectively.
The subjects were then divided into 2 groups, above (above group) or below (below group) 30%, 31%, 32%, 33%, 34% or 35% body fat. Wherever the subjects were divided into 2 groups at these values of %fat, the above group showed a significantly higer occurrence of abnormal values for medical parameters than the below group.
The subjects were further divided into 3 groups: 154 subjects with %fat below 29.9% (N group), 47 subjects with %fat between 30% and 34.9% (MO group), and 49 subjects with %fat above 35% (O group) . The O group showed significantly higher occurrence of abnormal values for medical parameters than the MO and N groups. The O group also showed a significantly higher mean value of DBP than the MO and N groups. Furthermore, the O group showed a significantly lower mean value of HDL-C and significantly higher mean values of TC/HDL-C, UA, GOT, GPT, SBP, FBS than the N group. There was no significant difference between the N and MO groups in the occurrence of abnormal values for medical parameters. However, the MO group showed a significantly lower mean value of HDL-C and significantly higher mean values of TC/HDL-C, UA and β-L.
These results suggest that the values of medical parameters become poorer when %fat exceeds 30%, a level widely used in Japan as a criterion for evaluation of obesity.
The subjects were further divided into 3 groups: 50 subjects who were non-obese and fit (NF group) ; 104 subjects who were non-obese and unfit (NU group) ; 88 subjects who were obese and unfit (OU group) . There were significant differences in the occurrence of abnormal values for medical parameters among these groups. The NF group showed the lowest values, followed by the NU and OU groups. Thus, it seems preferable to evaluate individuals using a combination of %fat and VO₂max/wt.

A study was conducted to derive a criterion for evaluation of obesity based on relationships between percent body fat (%fat) and clinical parameters. The subjects were 457 men aged 18 to 73 years. The results obtained were as follows:
After controlling for the effects of age, maximal oxygen intake per kilogram body weight (VO₂max/wt), alcohol intake and cigarette smoking, %fat showed significant correlations with high-density lipoprotein cholesterol (HDL-C), total cholesterol/HDL-C ratio (TC/HDL-C), fasting blood sugar (FBS), glutamic oxaloacetic transaminase (GOT), glutamic pyruvic transaminase (GPT), γ-glutamyl transpeptidase (γ-GTP), white blood cell count (WBC), red blood cell count (RBC), systolic blood pressure (SBP), and diastolic blood pressure (DBP) . Values of %fat estimated from borderline values of these clinical parameters ranged from 17.9% to 20.4%.
When the subjects were divided into 11 groups from a below 12% fat group to an above 22% fat group, the 18%, 20%, 21% and above 22% fat groups showed significantly higher occurrence of abnormal values for clinical parameters than the below 12% fat group.
When the subjects were divided into 2 groups, i, e, above (above group) or below (below group) 18%, 19%, 20%, or 21% body fat, the above group always showed a significantly higher occurrence of abnormal values for clinical parameters than the below group.
The subjects were further divided into 3 groups: 250 subjects with %fat below 17.9% (N group), 63 subjects with %fat between 18% and 19.9% (MO group), and 144 subjects with %fat above 20% (O group) . The O group showed the highest occurrence of abnormal values for clinical parameters, followed in order by the MO and N groups. These differences were significant. The O group showed a significantly lower mean value of HDL-C and significantly higher mean values of TC, TC/HDL-C, TG, GPT, SBP, DBP and FBS than the N group. The O group also showed significantly higher mean values for WBC and RBC than the MO and N groups. The O and MO groups showed significantly higer mean values of β-L, γ-GTP and UA than the N group.
From these results and the fact that a value above 20% fat is widely used as a criterion for evaluation of obesity, men with a %fat range of 18.0% to 19.9% are defined as mildly obese, whereas those with above 20% fat are defined as obese.
The subjects were further divided into 3 gooups: %fat below (non-obese) or above (obese) 20%, and VO₂max/wt above (fit) or below (unfit) values recommended by the Ministry of Public Welfare for each age group. One hundred fifty-one subjects were non-obese and fit (NF group), 142 subjects were non-obese and unfit (NU group) and 107 subjects were obese and unfit (OU group) . The NF group showed the lowest occurrence of abnormal values for clinical parameters, followed in order by the NU and OU groups. These differences were significant. Thus, it seems appropriate to evaluate obesity by using a combination of %fat and VO₂max/wt.