Not-so-sweet: Could diet drinks promote weight gain by encouraging us to overcompensate? A new study shows that this may be the case in rats.
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SYDNEY: Rather than helping fight the bulge, diet soft drinks and foods made with low-calorie (low-kilojoule) sweeteners may actually promote weight gain, a new study has revealed.
The controversial findings, published in the February edition of Behavioral Neuroscience, appear to contradict the much-promoted message that calorie-reduced food and beverages can be used as a means of weight control.
The sweetness and energy link
Early in life we learn to associate the sweetness of a food with its calorie density, and thus the consequences of digesting it, said study authors, Susan Swithers and Terry Davidson, psychologists at the Ingestive Behaviour Research Centre of Purdue University in Indiana, USA. Therefore we learn that the sweeter the food, the greater the number of calories it contains.
But with the abundant consumption of sweet, low-energy diet drinks and foods, the sweetness/calorie link could be severed, confusing the body and leading to difficulties controlling energy intake and body weight, they said.
To investigate, Swithers and Davidson took 27 rats and fed them over five weeks with different types of yoghurt, in addition to regular feed and occasional high-energy treats.
One group was given plain and glucose-sweetened yoghurt, so that sweet flavoured food became associated with a higher calorie consequence (glucose contains about 63 kJ per teaspoon). Another group was fed with plain and saccharin-sweetened yoghurt. Since saccharin is calorie-free, this group was not conditioned to associate sweetness with energy.
Impaired ability to compensate
The researchers discovered that rats that hadn't learnt to associate sweetness with high-energy foods demonstrated an impaired ability to "compensate" for high calorie meals. This meant that, unlike the glucose-fed rats, they failed to limit further food intake after consuming a sweet, high-calorie meal.
They also experienced a dampened metabolic 'preparedness' for high-energy food, making it harder for them to burn it off and causing them to over-eat. At the end of the study, the experts found that the saccharin-fed rats had had a higher overall calorie intake and had gained more body weight.
Though these findings suggest that calorie-reduced sweeteners may in fact have a counterintuitive effect when it comes to dieting in humans, the researchers noted that "the generality of findings obtained with rats in the laboratory to humans in their much more complex food environments can and should be questioned."
And, in fact, a new review of many different human trials of low-calorie sweeteners, published last week in the European Journal of Clinical Nutrition, concluded in contrast that sweeteners are helpful in fighting rising obesity rates.
I couldn`t even imagine that
I couldn`t even imagine that diet drinks may promote weight gain.
Nevertheless it is always better to drink fresh organic juice or water.