Cutting out certain foods after the festive period is not likely to be productive, it has been claimed.
Jenny Caven, a spokeswoman for Slimming World, said that restricting oneself in terms of diet can become problematic.
"Traditionally we believe that we need to punish or restrict ourselves by cutting out food types or go on a strict detox to lose a few pounds after Christmas," she noted.
"But the latest evidence shows that restricting yourself can be counterproductive and quickly lead you to fall off the wagon."
Ms Caven advised people wanting to lose weight to swap fatty foods for healthy alternatives such as pasta, vegetables, potatoes, lean meat, fish and eggs.
Alcohol, fast foods and snacks should be limited but not cut out completely.
Figures from Datamonitor show that two-thirds of Britons are overweight or obese. By 2014, a total of 16.5 million people in the UK will be classified as medically obese.