Studies of body-composition changes during weight loss have had conflicting results with regard to changes in bone mineral content (BMC) and bone mineral density (BMD). We examined BMC and BMD for changes during weight loss. Fourteen women enrolled in a 15-wk weight loss program. Dual-energy X-ray absorptiometry (DXA) measures of the total body were made at baseline (T1), the midpoint of weight loss (T2), and at the end of weight loss (T3). Body weight changed significantly throughout the 15 wk, declining from a high of 89.7+/-3.6 to 74.1+/-3.2 kg. Fat-free mass declined initially (47.8+/-1.7 kg at T1, 45.7+/-1.4 kg at T2, and 46.0+/-1.5 kg at T3) and then stabilized. Fat mass changed significantly during the study (39.2 kg at T1, 32.4 kg at T2, and 29.3 kg at T3). No significant differences were observed in BMC or bone areal measurement during the study. However, BMD declined significantly from baseline (1.217 g/cm2 at T1, 1.197 g/cm2 at T2, and 1.200 g/cm2 at T3). The changes in BMC and BA were in opposite directions, resulting in a significant decline in BMD without a loss of BMC. These data suggest that changes in BMD observed with weight loss may be the result of a lack of instrument sensitivity when body weight and composition change and are simply an artifact and not a physiologic change in BMD. Further research is needed to determine the full effect of weight loss on BMC, bone area, and BMD.

We analyse the content of Italian occupations operating in about 600 sectors with a focus on the dimensions that expose workers to risks during the COVID-19 epidemics. We leverage detailed information from ICP, the Italian equivalent of O*Net and find that several sectors need physical proximity to operate: the workers employed in sectors whose physical proximity index is above the national average are more than 6.5 million (mostly in retail trade). Groups at risk of complications from COVID-19 (mainly male above the age of 50) work in sectors that are little exposed to physical proximity, currently under lockdown or can work remotely. The sectoral lockdowns put in place by the Italian Government in March 2020 targeted sectors that operate in physical proximity, but not those directly exposed to infections (the health industry is not subject to lockdown). Most of the workforce who can operate from home have not been put under lockdown.

The purpose of this study was to determine whether meal ingestion pattern [large morning meals (AM) vs. large evening meals (PM)] affects changes in body weight, body composition or energy utilization during weight loss. Ten women completed a metabolic ward study of 3-wk weight stabilization followed by 12 wk of weight loss with a moderately energy restricted diet [mean energy intake +/- SD = 107 +/- 6 kJ/(kg.d)] and regular exercise. The weight loss phase was divided into two 6-wk periods. During period 1, 70% of daily energy intake was taken as two meals in the AM (n = 4) or in the PM (n = 6). Subjects crossed over to the alternate meal time in period 2. Both weight loss and fat-free mass loss were greater with the AM than the PM meal pattern: 3.90 +/- 0.19 vs. 3.27 +/- 0.26 kg/6 wk, P < 0.05, and 1.28 +/- 0.14 vs. 0.25 +/- 0.16 kg/6 wk, P < 0.001, respectively. Change in fat mass and loss of body energy were affected by order of meal pattern ingestion. The PM pattern resulted in greater loss of fat mass in period 1 (P < 0.01) but not in period 2. Likewise, resting mid-afternoon fat oxidation rate was higher with the PM pattern in period 1 (P < 0.05) but not in period 2, corresponding with the fat mass changes. To conclude, ingestion of larger AM meals resulted in slightly greater weight loss, but ingestion of larger PM meals resulted in better maintenance of fat-free mass. Thus, incorporation of larger PM meals in a weight loss regimen may be important in minimizing the loss of fat-free mass.

Energy expenditure (EE) was measured at specific steady-state work rates to determine if body fat percentage or gender was associated with exercise EE, substrate oxidation, or work efficiency. Body fat percentage (leaner vs. fatter men, 9-15% vs. 20-25% fat; leanervs. fatter women, 1624% vs. 32-48% fat) was not related to work efficiency or submaximal EE. Fatness affected substrate oxidation in men but not in women. Compared to fatter men, leaner men had higher fat oxidation (6.7 f 1.6 vs. 1.4 f 2.0 mg . kg fat-free mass [FFMI-' . min-';p < .Ol) and lower carbohydrate oxidation (26.6 f 4.2 vs. 39.3When men and women of similar fatness and relative aerobic capacity were compared, men had higher EE measured as kilojoules per minute but similar rates of EE and substrate oxidation per kilogram of FFM at 40-60% ~0 , m a x .It was concluded that body FFM, not fatness, is adeterminant of exercise EE, whereas fatness is associated with differences in exercise substrate oxidation in men. Along with aerobic fitness, gender and fatness should be considered in future studies of exercise substrate oxidation.It is well known that body fat-free mass (FFM) is a chief determinant of metabolic rate (23), but little is known about the relationship between fat mass and energy expenditure and utilization. According to Flatt (9), enlargement of the fat mass increases the availability of free fatty acids as metabolic fuel and promotes fat oxidation. However, in one study conducted in a respiratory chamber under conditions of low physical activity, percentage body fat was related to fat oxidation (22), and in another study it was not (21). Further, the relationship between fat mass and energy utilization during physically active periods is not well defined in humans. More studies in this area are needed, particularly since Flatt (10) proposed thatThe authors are with the USDA, ARS, Western

The effect of energy content and protein concentration of a test meal and exercise intensity on the thermic effect of food (TEF) was examined. TEF was measured in eight men in response to meals representing 15, 30, and 45% of daily energy requirement; protein concentrations of 15, 30, and 45% of energy of the meal, and exercise intensities of 35, 50, and 65% of maximum capacity. In response to energy content of the meals, total 3-h TEF (mean +/- SEM) 4.0 +/- 0.83, 9.7 +/- 1.15, and 10.8 +/- 0.79 1 O2 for the 15, 30, and 45% meals, respectively, indicating a positive linear and a negative quadratic relationship. Although the 15% protein meal resulted in the smallest TEF, 150-270 min after the meal, total 5-h increase in oxygen consumption did not differ among the three protein meals. Exercise intensity did not alter TEF. Energy content of the test meal had the greatest effect on TEF.