Most people on a diet would simply try to eat less than usual - running the risk of binge-eating once their willpower runs out - but eating behaviour expert Ciaran Forde takes a very different approach to careful eating.

His reasoning: If people do not feel that they are giving up anything, they would not feel the need to compensate for it later on.

To test this hypothesis, he served bowls of ramen to 27 hungry university students for lunch on three different occasions.

All the bowls looked and tasted identical but the catch was that some had up to seven times more calories than others, even though the portions were exactly the same.

This was done by tweaking the ingredients: chicken breast instead of breaded chicken in low-calorie meals, for example, and more sesame seeds in high-calorie ones.

One would expect the students given the low-energy meals to make up for the deficit by eating more at dinner afterwards. Instead, no significant differences in their eating patterns were observed.

What this shows, said Associate Professor Forde, who is from the Clinical Nutrition Research Centre housed on the National University of Singapore campus, is that people generally do not compensate for energy removed from their food.

In other words, as long as their senses tell them they are not being shortchanged on food - even when their calorie intake is less - they would not feel the need to make up for it within the same day.

"What we have done is to maintain the sensory properties of food," said Prof Forde. "Then we can support a calorie-reduced diet by concealing missing energy and sustaining satisfaction and liking for the foods."

He added: "People don't seem to miss anything and why would they? The volume, appearance, smell and taste are the same, so they have no major incentive to eat extra food."

In contrast, people on diets tend to feel like they are making a sacrifice, giving them a reason to eat more on their "cheat days".

The centre where Prof Forde works is a $20-million joint venture by the Agency for Science, Technology and Research (A*Star) and the National University Health System, which was opened in 2014.

It focuses on food and nutrition research. It has a laboratory for food analysis and specially-designed facilities to measure a person's metabolism and body volume, which estimates the lean and fat mass from his height and weight.

It is important for nutritionists to know a person's "body volume" because it is not healthy to have too much fat mass relative to lean mass, such as muscles and bone.

Prof Forde, a principal investi- gator in sensory nutritional science at the centre, had his study findings published last month in international journal Physiology & Behaviour.

His study suggests that all people could have a "calorie threshold", a certain point at which a higher caloric intake does not translate into greater feelings of satisfaction.

His team is trying to pinpoint this threshold more accurately.

The knowledge could eventually be combined with what researchers already know about how our senses react to food, helping people trying to lose weight feel completely satisfied with a minimal calorie intake.

For example, said Prof Forde, our minds very easily convince us that small portions of food, or food labelled as "low-calorie", are not going to make us feel full - even before the food enters our mouth.

"It's a cognitive cue because if it looks small, it looks unsatisfying and I feel unsatisfied before I even put the first spoonful in my mouth," he said. "Calling it "low-calorie" also primes me to feel hungrier."

In fact, said Gleneagles Hospital dietician Daphne Loh, our senses can play a huge role in determining how much we eat.

Studies have shown that people given large plates tend to help themselves to larger portions of food because the food appears smaller on the plate than it actually is.

"Whereas, smaller plates can lead us to misjudge that very same quantity of food as being significantly larger," she said.

Even the colour of a plate can have an impact, she said, adding that people subconsciously eat more when food blends in with the crockery it is placed on.

"Plates with a contrasting colour to the food makes the person more aware of the portion size, hence they are less likely to over-serve themselves," Ms Loh said.

People find it difficult to stick to diets, said Prof Forde, because they often require wide-ranging changes in behaviour.

A more effective way to lose weight, he suggested, is to look at the energy content of favourite foods and see how you can cut the calories while still feel satisfied enough to not go on a binge.

Prof Forde said: "Fundamentally, we are eating with our eyes, nose and tongue, and as long as we maintain liking, it should be possible to reduce our energy intake."