A new survey has revealed that dieters are consuming more than a quarter of their weekly calorie intake in booze alone. Although it may feel like a glass of wine or a pint of beer is the perfect way to unwind after a long day at work, there are often more calories in alcohol than we first think, and that is before all the junk food that inevitably follows a trip to the pub.

The results are revealed in a survey of 1,000 slimmers conducted by UK diet firm FORZA Supplements, which shows excessive alcohol consumption is a key factor in people piling on the pounds.

A staggering 81% of respondents admitted that alcohol destroys their willpower and ruins their diet plans, with more than half blaming the booze for making them hungrier and far more likely to have a fattening takeaway afterwards. The survey found that 42% of us let ourselves go at least once a week, consuming a whopping 1,000 calories in alcohol alone on a night out with friends. It also found that 34% of us drink alcohol at least three times a week - most commonly to unwind and relax after a hard day at work.

The most popular drink for women is a large glass of white wine (185 calories per 250ml glass) and a pint of lager for men (230 calories). Most people will have two glasses of wine or two pints of beer on a typical week day night, while drinking increases noticeably at weekends. A quarter of those surveyed said that they drank excessively twice a week and 15% admitted to have a heavy night of alcohol three times a week.

For men, this means consuming around 1,150 calories in one session (five pints), which is roughly half of their daily calorie intake of 2,500 calories. Women will typically drink three glasses of wine (55 calories), plus a cocktail (260 calories) and a shot of spirits and mixer (120 calories for a vodka and coke). This amounts to 935 calories, or just less than half of their daily calorie intake of 2,000 calories. The reason that excess boozing is so damaging to diets is because it makes us deviate from our diet plans and consume more food than planned.

Three quarters of us have a takeaway after a night out - typically a burger (490 calories), pizza (675), two pieces of fried chicken (400) or a bag of chips (312). Over the course of a week’s boozing, 26% of dieters typically consume a quarter of their weekly calorie intake in alcohol alone.

FORZA Supplements Managing Director Lee Smith said that there was a scientific explanation for why we eat more when we drink excessively. He said: “Studies show that alcohol increases your appetite by suppressing leptin, the hormone which tells your brain to stop eating and negatively affects many other brain chemicals that are involved in appetite suppression.

“It also rather famously makes us lose our inhibitions, making the decision to grab a slice of pizza or order those chicken wings all the more easy.

“The other really damaging thing is that as few as two standard alcoholic drinks can slow down your body’s fat-burning process by a whopping 73%. “Your liver recognises the by-products of alcohol as toxins, so your body stops processing nutrients from the food you’ve eaten while it takes care of the ‘bad guys’ first.

“As a result, your body burns empty alcohol calories (those low in nutrients) for energy while the digestion of nutrient-rich food is put on the back burner. “By the time your body gets round to burning food calories, it might not need the energy and ends up storing the extra calories you’ve eaten as fat cells. 

"So the key to successful dieting is cutting out the booze. But that is far easier said than done.” FORZA Supplements make Raspberry Ketone 2:2:1, the UK’s best-selling brand of diet pills. The diet capsules were recently used by The Apprentice star Luisa Zissman to lose a stone. She described them as “willpower in pill form”.