A quarter of gym users actually put on weight when they start exercising, according to a new study. The survey, conducted by leading UK diet firm FORZA Supplements, revealed that gym-goers pile on the pounds because they allow themselves ‘treats’ after a workout. Almost 40% of people burn as little as 300 calories during each visit to the gym, making them susceptible to weight gain if they then immediately treat themselves to a high-calorie snack.

Empty gym with weight equipments

The poll found that the ‘feeling of complacency’ that comes with regular gym sessions made it more difficult for dieters to stick to their recommended daily calorie intake. Of the 1,000 gym users who were polled, it was found that 26% of people actually put on weight after starting a regular exercise programme.

A further 49% admitted that their weight had stayed the same since starting exercise, while just 25% said that they had lost any weight at all. The survey revealed that most keep-fit fans go to the gym between three and four times a week, exercising on average for between 40 minutes and an hour. Four out of ten gym-goers burn between 300 and 500 calories per session – though 25% manage only 200 to 300 calories, 10% just 100 to 200 calories and 4% less than 100 calories.

The rest of the figures were: 300-400 calories (41%), 500-700 calories (14%), 700-1000 calories (3%), and more than 1000 calories (1%). To make matters worse, 35% of people allow themselves a treat after going to the gym, most typically a chocolate bar, such as a Kit Kat (233 calories for a four finger bar), a glass of wine (190 calories) or a pint of lager (230 calories).

Another reason why going to the gym can negatively affect your weight is the fact that users have far bigger appetites than those who do not exercise, meaning that they are more likely to overindulge and consume more calories than they used up by exercising. The poll revealed that 53% of people had substantially larger appetites after exercise sessions, while almost half admitted to working out prior to a big night out in order to ‘compensate’ for the calories that they would consume.

Luisa Zissman, star of The Apprentice 2013, said: “Who hasn’t had a guilt-inspired exercise session? “We all do it - work out furiously in the gym to get ‘brownie points’ ahead of a night’s partying. “You know you are going to consume a stack of calories by boozing and drinking - so why not burn off a load beforehand.” But it is not just celebrities who take this point of view about the gym.

By exercising regularly, 42% of dieters feel that they have earned the right to deviate from controlled diet plans. FORZA Supplements Managing Director Lee Smith pointed out that the survey showed how many dieters struggle to lose weight despite regularly exercising.

He said: “Battling the bulge is the toughest things that many of us do. Lots of people go to the gym because they know they have no control over their eating habits. “They figure, ‘I am going to pig out anyway so I may as well do my best to limit the damage’. Many gym-goers underestimate the level of exercise that is needed to shift fat. “To lose 1kg of body fat, you need to burn about 8,000 calories - that is around 80 miles of running to cover just 1kg in weight. “This is where diet supplements really come in handy. Not only do they make gym sessions more productive, but they give valuable support outside of the gym when people are more likely to get side-tracked.”