Daily physical activity assessment in free-living subjects : comparison between movement registration and doubly labeled water

The use of movement registration for daily physical activity assessment was evaluated during a 7-day period in 30 free-living subjects. Body movement was registered with a Tracmor motion sensor consisting of a triaxial accelerometer and a data unit for on-line processing of accelerometer output over 1-min intervals. Average Tracmor output was correlated against four different energy estimates: 1) average daily metabolic rate (ADMR), determined with doubly labeled water; 2) ADMR-sleeping metabolic rate (SMR; determined in a respiration chamber); 3) (ADMR-SMR) per kilogram of body mass; and 4) the overall physical activity level (PAL = ADMR/SMR). The highest correlation was found for the relationship between Tracmor output and PAL (r = 0.58). After correction for Tracmor values arising from vibrations produced by transportation means, this correlation was improved to 0.73. There was no difference between Tracmor output and PAL in discriminating between overall activity levels with "low" (PAL <1.60), "moderate" (1.60 <or = PAL <or = 1.85), and "high" (PAL > 1.85) intensity. It is concluded that the Tracmor can be used in free-living subjects to distinguish among interindividual as well as intraindividual levels of daily physical activity

Long term effects of consumption of full-fat or reduced-fat products in healthy non-obese volunteers: assessment of energy expenditure and substrate oxidation.

Long-term effects of consumption of full-fat or reduced-fat products in healthy non-obese volunteers: assessment of energy expenditure and substrate oxidation. Verboeket-van de Venne WP, Westerterp KR, Hermans-Limpens TJ, de Graaf C, van het Hof KH, Weststrate JA. Department of Human Biology, University of Limburg, Maastricht, The Netherlands. A study was performed to evaluate long-term (6-month) effects of consumption of full-fat products or reduced-fat products on energy and substrate metabolism. Subjects (age, 19 to 35 years; body mass index [BMI], 21 to 28 kg. m-2) were studied during a 36-hour stay in a respiration chamber, before (16 men) and in the third month (16 men) and sixth month (19 men and 17 women) of the study. The diet intervention caused, on average, a change in fat intake of (mean +/- SE) +23 +/- 31 g/d (P < .001) in the full-fat group and of -5 +/- 29 g/d (P .05) in the reduced-fat group. Twenty-four-hour energy expenditure (EE), sleeping metabolic rate (SMR), diet-induced thermogenesis (DIT), and EE for physical activity (ACT) were not different between the groups. Fat oxidation was significantly (P < .05) increased in the full-fat group and was not different from fat intake. During the 6 months of the study, body mass and fat mass were significantly increased in subjects of the full-fat group, whereas there were no changes in body mass or body composition in subjects of the reduced-fat group. It is concluded that in the long run, avoidance of a diet with full-fat products will promote body weight and fast stability

A comparison of the effect of free access to reduced fat products or their full fat equivalents on food intake, body weight, blood lipids and fat-soluble antioxidants levels and haemostasis variables

Objectives: To compare the effects of free access to reduced fat products or their full fat equivalents on fat and energy intake, body weight, plasma lipids and fat-soluble antioxidants concentrations and haemostasis variables. Design: A multicentre open randomised controlled trial in which intervention and control groups were followed in parallel for six months. Volunteers had free access to 44 different foods either in reduced fat or full fat version, covering between 30 and 40% of energy intake. The remainder of energy intake was covered by foods bought in regular shops. Setting: Zeist, Wageningen and Maastricht, The Netherlands. Subjects: Two hundred and forty-one non-obese healthy volunteers who had no intention to lose weight. Main outcome measures: Food intake, body weight, plasma lipid, vitamin E, β-carotene, lycopene and fibrinogen concentrations, plasma factor VII clotting activity, and plasminogen-activator-inhibitor-I antigen level. Results: One hundred and three volunteers in the full fat group and 117 volunteers in the reduced fat group completed the study. Energy and fat intake from the free access products was lower in the reduced fat group, but no difference in energy and fat intake of other products occurred. Body weight, energy-, fat- and vitamin E intake and percentage of energy derived from fat decreased in the reduced fat group. No other statistical significant intervention effects were observed. Blood lipid concentrations, factor VII activity and plasminogen-inhibitor-activator-1 level were reduced after consumption of reduced fat products. Conclusions: When subjects without intention to lose weight limit fat intake by switching from ad libitum consumption of full fat products to reduced fat products body weight gain is prevented, and fat and energy intake are reduced. Such a switch may have beneficial effects on biochemical cardiovascular risk factors. We concluded that reduced fat products will help in a population strategy aimed at preventing overweight and obesity, they will also be effective in maintaining a lower body weight after slimming. Ad libitum consumption of reduced fat products will be ineffective for those individuals that want to reduce body weight because they are currently overweight or obese. Sponsorship: Unilever