As surprising as it may sound, for some people the problem of weight gain may lie right on the tip of their tongue.
There are many things that can influence a person’s desire for food. When given a choice between foods, the desire to choose one food over another is closely linked to taste and other sensory signals such as smell and the feel of the food in the mouth.
A very simple hypothesis posed by obesity researchers is that as people gain weight, their taste perception changes. This theory is supported by studies in both animals and humans and suggest that obese people may not detect sweet tastes as well as their lean counterparts. This partly could be because of genetic factors, but also from changes in taste sensitivity as people gain weight.
To support the taste-change hypothesis, showing an actual biochemical change in the functioning of taste receptors would be an important piece of evidence. And that’s just what researchers have done with mice who were fed a high-fat diet  over 10 weeks to make them obese.
Using special molecular detection techniques, the researchers could isolate taste cells and study how responsive they were to taste stimuli. Fewer taste cells from the obese mice were sensitive to the effects of sweet tastes. What’s more, the cells that were still responsive to sweetness had a blunting in their response. A similar effect was seen in response to recognition of fatty acids and also the taste of bitterness.
What it all means
This research makes a stronger case for taste changes being either a consequence or a partial cause of obesity. If a person is less able to detect tastes such as sweetness, it may mean they will need to eat more to get the same ‘taste sensation’ they had when they were thinner. Understanding how taste cells are affected by weight gain opens the door for research into ways to ‘reset’ taste sensitivity.
Confused about the mixed soup of nutrition messages being stirred through the media? Tim maintains an active nutrition blog at www.thinkingnutrition.com.au  where you'll find the latest nutrition research and controversies discussed in straight forward language, distilling out what you need to know for your better health.