Results of an interesting weight loss study presented at The Endocrine Society's 90th Annual Meeting in San Diego, suggests that people can lose weight by flavouring their food with calorie-free seasonings and sweeteners, which may make them feel full faster, so reducing their consumption. The Sensa® diet, developed by Dr Alan Hirsch, was given to 1,436 overweight or obese subjects for a period of 6-months. Study subjects were required to sprinkle a variety of savoury or sweet crystals – called Sensa® “tastants” - on their food before eating their meals during the 6-month study period. Subjects did not know what the flavours were other than salty or sweet. The hidden flavours of the savoury tastants were cheddar cheese, onion, horseradish, ranch dressing, taco or parmesan. Sweet flavours were cocoa, spearmint, banana, strawberry, raspberry, and malt. A control group of 100 volunteers did not use tastants. Both groups were allowed to diet and exercise if they were already doing so. For both subjects and controls, Hirsch measured weight and body mass index (BMI) - a measure of height and weight - before and after the study.
According to Hirsch, after 6 months of using the crystals, the 1,436 subjects who completed the study exhibited an average weight loss of 30.5 pounds, compared with just 2 pounds for the untreated controls. Their BMI dropped by an average of 5, moving them from obesity to the overweight range. Controls had an average BMI decrease of 0.3.
Hirsch theorized that subjects lost more weight than controls did because the tastants made them feel full faster and therefore eat less. However, he did not track the amount of food the subjects ate. Another possibility, he said, is that the crystals improved the taste of bland but healthy foods, such as tofu and some vegetables, causing a change toward healthier eating habits. He said he believes this approach works because, unlike most diets, it is not based on food restriction.
What should we make of this? A few points might begin to set this “trial” in context. Firstly, notice that the study was carried out under the supervision of Dr Hirsch, the same person who is likely to benefit from sales of Sensa®. It would have been prudent for him to have had the study carried out – or at the very least supervised – by an independent academic institution. Secondly, the subjects in the study weighed themselves and reported their own weight loss without any objective checks. Thirdly, the Endocrine Society which Hirsch says reviewed and approved of his work said they merely invited him to present his findings for debate and they were "surprised and troubled by the promotional nature of his presentation."
Finally – and most important of all - Dr Hirsch’s study has not been “peer reviewed”. Whenever one wishes to publish a scientific paper, one must subit one’s work to an independent group of experts working in the same field, so that they can judge the merit of the data. If it does not stand scrutiny, the paper will not be published. So clearly, Dr Hisrch’s work has not been peer reviewed and, by definition, has never been published in a reputable scientific journal.
So, if Dr Hirsch is confident that his Sensa® crystals work, he must be willing to support an entirely independent scientific study to see if his results can be repeated. This is the only possible way that anyone will take it seriously (and I certainly don’t).
As the physicist W. Edwards Deming put it “In God we trust; all others must bring data”
Dr David Ashton
23rd November 2010
