Reaching and maintaining an ideal body weight could be restricted by the body’s defence mechanism, which holds onto the final few pounds to guard against starvation, according to a group of diet experts.

In an article published by the Washington Post, specialists have described how the body becomes accustomed to a certain weight over an extended period of time and will try to defend that weight against dieting measures.

This potentially makes dieting and keeping body weights at a certain level more difficult, as dieters may reach their required target, but then find it difficult to maintain this level of weight loss as calorie restrictions become too severe once the body starts fighting the losses.

“I often ask patients, ‘What is the lowest sustained weight of your adult life?’ to get an idea of what is realistic” in terms of weight loss and maintenance,” says Claire LeBrun, a registered dietitian and senior nutritionist with the Department of Surgery at the GW Medical Faculty Associates.

“That’s why it’s important to set realistic goals. The idea of the ‘ideal weight’ or ‘dream weight’ is really just an exercise in futility.”

According to LeBrun, the body’s yardstick can be altered, though, but this can take up to six months of maintenance for the body to get used to its new “set weight”.

However, for those still finding their weight plateauing after active measures, nutritionists have also suggested re-evaluating nutrition and exercise plans.

“Maybe you are getting a little sloppy? Maybe you feel that you have been good for so long that you are letting some old habits back in?” says dietitian Lise Gloede in the article.

Drops in resting metabolic rates can also cause issues too as fewer calories are needed the less people weigh; meaning that dieters will need to decrease calorie consumption as they lose weight, while also looking to increase their calorie-burn.

Looking to maintain lean muscle mass could also be beneficial, as it helps to continue calorie-burn.

“It’s also about body composition, not just weight,” adds James Rippe, a cardiologist and dieting author.

“As you lose fat you want to maintain lean muscle mass through both strength training and aerobic conditioning.”