Metabolic responses to food and acute cold stress.

Ten subjects aged 19-35 years (four men and six women) underwent two measurements of 24 h energy expenditure (EE) in a whole-body respiration calorimeter, one at a temperature of 28" and one at 20". Choice of clothing was allowed. Dietary intake was standardized and subjects were asked to follow the same pattern of activity during both measurements. Mean 24 h EE was significantly greater a t the cooler temperature by 5.0 (SD 5.5) ' 3' 0, with individual differences ranging from 4.6 YO lower to 12.6 % higher.The difference in E E a t the two temperatures was similar during the day and the night and occurred even though subjects wore more clothes and used more bedding at 20". No relationship was observed between response to 20" and body-weight status. In conclusion, the assumption that mild cold is unlikely to affect EE in subjects wearing normal clothing may be incorrect.Energy expenditure: Environmental temperature

mentioning

confidence: 99%

Influence of mild cold on 24 h energy expenditure in ‘normally’ clothed adults

Warwick

Busby

1990

“…Studies have usually been made in Severe cold, when the effect of temperature on metabolic rate has been considerably greater than the effect of energy intake (Buskirk er al. 1960;Rochelle & Horvath, 1969).…”

mentioning

confidence: 99%

Influence of mild cold on 24 h energy expenditure, resting metabolism and diet-induced thermogenesis

Dauncey

1981

117

1. It has been suggested previously that people in developed countries do not expose themselves to cold severe enough to induce a metabolic response. The energy expenditure, as both heat production and total heat loss, of nine women was therefore measured continuously while each lived for 30 h in a whole-body calorimeter on two occasions, one at 2 8 O and the other at 22". All subjects followed a predetermined pattern of activity and food intake. The environmental conditions were judged by the subjects to be within those encountered in everyday life. In the standard clothing worn, 28O was considered to be comfortably warm but not too hot, while 22O was judged to be cool but not too cold. 2.Heat production for 24 h was significantly greater at the lower temperature, by (meanf SE) 7.0k 1.1 %. The range was between 2 and 12%. Total heat loss was also significantly greater, by 6%, and there was a large change in the partition of heat loss. At the lower temperature sensible heat loss increased by 29% while evaporative heat loss decreased by 39%.3. Resting metabolism measured in the morning 12-13 h after the last meal was significantly greater at 22O than at 28O, whereas there was no difference when the resting measurement was made for 2.5 h following a meal. 4.In conclusion : (a) environmental temperature may play a more important role than was previously recognized in the energy balance of those living in this country, and (b) there is an indication of at least a partial replacement of cold-induced by diet-induced thermogenesis in man.

“…Neither is H i E affected by shivering cold for short periods (at 108C compared with 268C); thus Buskirk et al (1960) showed in human subjects consuming a high-protein diet that H i E at the lower temperature was slightly higher that at the upper temperature, and suggested that H i E and shivering thermogenesis must operate additively and by different mechanisms. This finding was confirmed for a short period (2 h) at 78C compared with 258C with steak being the test meal (Rochelle & Horvath, 1969). Observations from Buskirk et al (1960), Rochelle & Horvath (1969), Dauncey (1981) and Valencia et al (1992) showed that for all practical purposes diet and cold thermogenesis in human subjects are additive.…”

Section: Dietary and Cold Thermogenesismentioning

confidence: 68%

“…This finding was confirmed for a short period (2 h) at 78C compared with 258C with steak being the test meal (Rochelle & Horvath, 1969). Observations from Buskirk et al (1960), Rochelle & Horvath (1969), Dauncey (1981) and Valencia et al (1992) showed that for all practical purposes diet and cold thermogenesis in human subjects are additive. It is of truly academic proportions that any interaction exists.…”

Section: Dietary and Cold Thermogenesismentioning

confidence: 68%

A perspective on food energy standards for nutrition labelling

Livesey

2001

Food energy values used for nutrition labelling and other purposes are traditionally based on the metabolisable energy (ME) standard, which has recent support from Warwick & Baines (2000). By reference to current practices and published data, the present review critically examines the ME standard and support for it. Theoretical and experimental evidence on the validity of ME and alternatives are considered. ME and alternatives are applied to 1189 foods to assess outcomes. The potential impact of implementing a better standard in food labelling, documentation of energy requirements and food tables, and its impact on users including consumers, trade and professionals, are also examined. Since 1987 twenty-two expert reviews, reports and regulatory documents have fully or partly dropped the ME standard. The principal reason given is that ME only approximates energy supply by nutrients, particularly fermentable carbohydrates. ME has been replaced by net metabolisable energy (NME), which accounts for the efficiency of fuel utilisation in metabolism. Data collated from modern indirect calorimetry studies in human subjects show NME to be valid and applicable to each source of food energy, not just carbohydrates. NME is robust; two independent approaches give almost identical results (human calorimetry and calculation of free energy or net ATP yield) and these approaches are well supported by studies in animals. By contrast, the theoretical basis of ME is totally flawed. ME incompletely represents the energy balance equation, with substantial energy losses in a missing term. In using NME factors an account is made of frequent over-approximations by the ME system, up to 25 % of the NME for individual foods among 1189 foods in British tables, particularly low-energy-density traditional foods. A new simple general factor system is possible based on NME, yet the minimal experimental methodology is no more than that required for ME. By accounting for unavailable carbohydrate the new factor system appears as specific to foods as the USA's food-specific Atwater system, while it is more representative of energy supply from food components. The NME content of foods is readily calculable as the sum from fat (37 kJ/g), protein (13 kJ/g), available carbohydrate (16 kJ/g), fully-fermentable carbohydrate (8 kJ/g), alcohol (26 kJ/g) and other components. Obstacles to the implementation of NME appear to be subjective and minor. In conclusion, the ME standard is at best an approximate surrogate for NME, and inadequately approximates food energy values for the purpose of informing the consumer about the impact on energy balance of the energy supply for equal intake of individual foods. NME is superior to ME for nutrition labelling and other purposes.Food energy: Food labelling: Net metabolisable energy Warwick & Baines (2000) propose that energy factors used for food labelling and other purposes should be based on a definition of metabolisable energy (ME). To some experts this proposal would seem sound, but to others it may be surprising....