Soft drinks - The Food Commission

scienceWhat the doctor readsThe latest research from the medical journalsExercise does notprevent obesityTwo papers from the Danish EpidemiologyScience Centre have examined the gradualonset of obesity in adults and found noevidence that physical activity patterns couldpredict who would gain weight, althoughobese people did take less exercise.Researchers monitored 6,000 adults acrossa 15-year period and also 2,000 men over a 40-year period. If anything, physical activitylevels were higher among those that laterdeveloped obesity.The researchers suggest that obesitydevelops from factors other than physicalinactivity or lack of exercise, but that onceestablished obesity leads to a reducedwillingness to take exercise – possibly due tothe discomfort of sweating andbreathlessness. Social factors – e.g. showingoneself in public changing rooms and gyms –may also be involved.■ H Bak et al, Int J Ob, 2003; L Petersen et al, Int JOb, 2004.25% cut in salt undetectedAn experiment in which the salt level inbread was cut by 5% every week for fiveweeks found that the reduced salt could notbe detected. Ratings of the saltiness and theflavour of the bread were no different tothose made by a control group whose breadwas not altered. The authors recommendthe bread industry to make small, repeatedadjustments to lower the overall salt burdenon the population, in order to reduce the riskof hypertension and stroke.■ S Girgis et al, Eur J Clin Nutr, 2003.Self-reported dietsunderestimate caloriesA comparison between the amounts of foodwomen said they were consuming and theamounts they would need according to theirweight, height and metabolic levels showedthat self-reported diets were typically morethan 400kcal per day below the expectedlevels.Over a quarter of women under-reportedby more than 800kcal per day. In the study (ofover 160,000 US women) those with higherBMIs tended to underreport more: at BMI 35underreporting was about 330 kcalories perday greater than at BMI 20.■ JR Hebert et al, Annal Epidem, 2003.Fast food is linked topoor dietA study of over 6,000 children showed thatthe diets of those eating fast foods is pooreroverall than the diets of those not eatingfast food, and that children have better dietson days that they do not eat fast food.On days when fast food was consumed,the survey of a nationally representativesample of US children found:higher energy intake (up 126 kcal/day)higher energy density (up 0.3 kcal/gram)more fat (up 7g/day)more saturated fat (up 3g/day)more added sugars (up 21g/day)more soft drinks (up 189g/day)smaller amounts of fruit and vegetables(down 47g/day).Typically, nearly a third of children reportedeating fast food on any given day.■ SA Bowman et al, Pediatrics, 2004.Organic plants containmore salicylic acidA comparison of commercial soups madeusing organic and non-organic vegetablesfound the former to have significantly higherlevels of naturally-occurring salicylic acid, theactive ingredient found in aspirin.Although levels were lower than would befound in pharmaceutical doses, if the overalldiet contains substantial amounts of organicproduce then the total effect may becomparable.Levels of salicylic acid in the blood of somevegetarians is as high as it is in some patientson regular low-dose aspirin prescribed forheart disease prevention.■ GJ Baxter et al, EFRC Bulletin, Dec 2003.Guidance sought oncalorie countingSeveral journalists and other individualshave contacted us over the past fewmonths asking how to calculate the amountof activity needed to burn off calories. Thefollowing chart shows approximate calorieexpenditure for a range of activities:Activity Kcalories used in 20minutes of activityAerobic dancing – lowintensity, equivalent to walking 80Aerobic dancing – mediumintensity, equivalent to jogging 130Aerobic dancing – high intensity,equivalent to running 170Bed making 100Cleaning windows 60Cleaning stairs 65Climbing stairs (72 steps per minute) 95Climbing stairs (92 steps per minute) 130Cycling on flat ground (‘own speed’) 125Dancing (waltz) 130Dusting 70Gardening 110Golf 100Knitting 25Office work (general) 25Operating electric sewing machine 25Playing cricket 160Playing pool 65Playing squash 200Playing tennis 140Playing football 140Playing table tennis 90Playing cards 40Running (speed unspecified) 190Sitting typing 30Walking on the level (1-2 km per hour) 45Walking on the level (4-5 km per hour) 85Watching football 40■ Source: Human Energy Requirements: Amanual for planners and nutritionists, byWPT James and EC Schofield, published bythe Oxford University Press (1990).Food Magazine 64 19 Jan/Mar 2004