Doubly Labelled Water - Gold Standard ?

Doubly Labelled Water (DLW) is said to be the "gold standard" of energy measurements but in the world of nutritional research that probably means it's just the least worst option. Most of the materials I've read propose it as a good measure of energy expenditure and it is then combined with body weight and composition changes to determine what the energy intake "must have been" using the calorie hypothesis.

DLW is in the news today as the UK Government's "Nudge Unit" - now operating independently as Behavioural Insights - has been looking at alleged under-reporting of calorie intake in official statistics.

One aspect of accuracy is how repeatable a measure is - if you take the same person and repeat a DLW test in the same circumstances do you get the same answer ? This has been done :-

Better results from low carb than lower fat.

 There's a lot of chatter over the pond and on t'internet about a recent study comparing low carbohydrate diet advice with reduced fat.

The work was led by Drs Bazanno and Hu of Tulane University, New Orleans and funded by the US National Institutes of Health. Its stated objective was

to examine the long-term effects of a diet low in carbohydrates, as compared to one low in fat, on cardiovascular disease risk factors, including blood pressure (BP), body weight and composition, serum lipids, plasma glucose, insulin, adipocytokines (adiponectin, leptin, resistin), and C-reactive protein (CRP) among obese adults.

All calories are not equal

I was recently drawn to read a report of a clinical trial of over-feeding, conducted by Bray et al of Pennington Biomedical Research Center. This was an inpatient study looking at the effect of protein on weight gain in people eating 40% more calories than required for maintenance of body weight.

This study was brought to my attention as evidence that the number of calories is more important than the composition of those calories, and it was said that "all the extra calories were from fat". On further examination I found that it actually shows something different.