The finding is based on the premise that different people digest fat and carbohydrate differently, and have different in-built appetite controls and muscle activity.
Weight loss can be increased by pinpointing those differences and adjusting the intake of the food metabolised least effectively, 'The Times' reported.
Researchers at the University of Trieste, in Italy, divided 200 overweight people into two groups for the experiment.
A standard diet plan was defined for both groups, taking away 600 calories from their usual energy needs.
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People who struggled to digest fats, for example, were given less fat in their diet without varying the overall amount of calories they ate, the report said.
Follow-up checks took place every six months over two years and showed weight loss over time with both groups sticking to their diet in a similar way.
However, those in the test group on the gene diet lost a third more weight than the control group.