Modeling transitions in body composition: the approach to steady state for anthropometric measures and physiological functions in the Minnesota human starvation study

Table 1 Kinetic parameters for endpoints from the Minnesota starvation study based on group averages (n = 32).

Quantity or Function	C12 mean	S12 mean	S24 mean	k (wk^-1)^a	Steady State
Body mass (kg)	69.39	57.28	52.57	0.079	49.6
Fat mass (kg)	9.84	4.57	3.04	0.103	2.41
Fat free mass (kg)^b	59.55	52.71	49.53	0.064	46.8
Body Mass Index^a (kg/m²)	21.7	17.92	16.44	0.078	15.5
Chest girth^b (cm)	89.28	83.69	82.61	0.137	82.4
Waist girth (cm)	78.08	71.23	70.7	0.213	70.7
Girth Sums^d (cm)	113.3	98	92.5	0.085	89.4
Active Tissue Mass^c (kg)	39.9	32.0	29.2	0.086	27.7
Red blood cells^c (kg)	2.74	2.11	1.99	0.138	1.96
REE^d (kcal/d)	1608	1100	994	0.131	966
Harvard work test	64.1	33.1	18.1	0.060	4.04
Hand dynamometer (kg)	58.2	47.2	41.8	0.059	36.6
N excretion (g/24 h)	13.17	8.12	7.42	0.165	7.31

Values for C12, the last week before energy restriction was imposed, were used as t = 0 in the model. S12 and S24 are the values recorded during the 12^th and 24^th weeks of energy restriction (t = 12 and 24 weeks, respectively).
^aAll parameter values were calculated from group mean data at C12, S12 and S24 by the 3 point method. Mean stature was 1.788 m.
^bFat free mass was calculated by subtracting measured fat mass from body mass.
^cActive tissue mass equals body mass minus the sum of fat mass, bone mineral, and thiocyanate space. Group data for active tissue mass, and red blood cell mass are from Table 152, and mean chest girths are from Table 49 [1].
^dSum of girths of calf, arm and thigh. REE, resting energy expenditure.