Why healthy foods seem less satisfying

In research that will shock, well, no-one really, psychologists from Yale University in the US have found that foods perceived as "healthy" leave us feeling hungry and dissatisfied whether they're actually healthy or not.

The results of the research suggest foods that people believe are indulgent produce a greater sense of gratification once consumed — even if they were in fact healthier than the "healthy" food, the researchers wrote in the journal Health Psychology.

The 46 participants in the study were given two 1600-kilojoule milkshakes that were exactly the same but were told they had varying nutritional content. One was described as a low-fat and "guilt-free" 600 kilojoules while the other was an "indulgent" 2600 kilojoules.

After both samples were taste-tested, blood samples of the participants showed levels of the hormone ghrelin declined when they thought they were drinking a decadent treat, meaning their stomach signalled they were full and satisfied rather than still hungry. When they consumed the "healthy" shake, levels stayed the same.

This research gives us a clue as to why our diets so often fail. When we believe we're eating something low in kilojoules, our body psyches us into thinking we aren't full, so we reach for something extra. And extra, and extra.

There you have it, a diet tip from the academics: Just believe that salad sandwich is in fact a Double Quarter Pounder and you'll be much more satisfied.