Behavioural scientists at the CSIRO say perfectionists are the least likely to achieve diet success.

Perfectionists are most likely to fail on a diet while foodies are more likely to be a normal weight.

Over-thinking and fear of failure stops most perfectionists achieving their weight loss goal, according to a new CSIRO survey of 28,000 people.

The study found nine out of 10 adults attempted to lose weight in their lifetime.

Half made more than six attempts, while almost 20 per cent tried more than 25 times.

Among the five "diet types" identified it's the "over-thinkers", or perfectionists, who were the least likely to achieve diet success.

The 'thinker' diet type was the leading type among 41 per cent of adults.

The second most common type, 'the craver' scored high for people who were obese, while 'the foodie' type were more likely to be a normal weight.

People who identify with the 'thinker' diet type are goal-oriented and analytical.

Yet these same qualities can be counterproductive to achieving diet goals, because they tend to set unrealistic expectations and give them little margin for error, behavioural scientists say.

This type is also more prone to self-doubt, anxiety and stress, which can lead to over-eating and low success, say the scientists.

"If you have struggled to maintain your diet after a few weeks, your personal diet type will shed light on what behaviours and habits are creating a barrier for you," CSIRO behavioural scientist Dr Sinead Golley said.

"Knowing your personal diet type helps you maintain a healthy eating plan because you are more aware and equipped to manage moments of weakness."

Dr Golley says if people identify as a 'thinker', they should reflect more on positive changes to manage their healthy eating habits and weight-loss goals.

The CSIRO's diet type online survey was launched last month and can be accessed at www.totalwellbeingdiet.com.

THE FIVE MAIN DIET PERSONALITY TYPES

• The Thinker - 41% - overthinking and worrying about failure leads to stress which can derail diet progress.
• The Craver - 25% - craves delicious food and finds it hard to stop, leading to overeating in tempting situations.
• The Foodie - 15% - loves making, eating and experiencing food.
• The Socialiser - 15% - flexibility is essential - you won't let strict food restrictions stifle your social life.
• The Freewheeler - 4% - makes spontaneous and impulsive food choices, finds planning meals hard.