There’s a great many reasons why a woman's weight may fluctuate. Some might say it's a hectic work schedule preventing them from getting to the gym.

Others may suggest it's the temptation of the office chocolate machine.

But research suggests there's only one real reason - their men.

A study into the ups and downs of the female weight-cycle showed happiness - or the lack of it - in a relationship is the biggest factor.

The report found early courtship usually brings with it a strict diet regime resulting in the loss of around 5lb.

After women enter Stage 2, which is the comfort zone, when they feel secure enough to relax a little, can put on a few pounds.

Wedding plans mean another sprint to shed a few pounds before the arrival of a baby reverses that weight loss, followed by a reinvention - which again sparks a diet drive.

The five stages of weight fluctuation, which can vary over around two stone, emerged in a study of 3,000 women by UK weight management firm www.slendex.com.

'Our emotions and relationships have an enormous effect on our health and above all our weight,' said Jane McCadden, of Slendex.

女性的体重变化受到很多因素的影响。有些人可能会认为，这是因为女性工作太忙没时间健身。

也有一些人认为，这是因为女性禁不住办公室巧克力机的诱惑。

但一项最新研究表明，真正的原因只有一个——那就是她们的爱人。

一项针对女性体重波动的研究显示，爱情幸福与否是影响女性体重变化的最重要因素。

研究发现，女性在“恋爱初期”通常会控制饮食，这一阶段她们的体重会下降5磅。

而在进入第二个阶段即“舒适期”后，安逸稳定的生活会让她们放松下来，同时体重也会随之增加。

到了结婚筹备期，女性的体重又会减掉几磅；而生了宝宝后，她们的体重又会大增，只有等到“再造期”重塑美丽身材了。

研究显示，女性的体重在这五个阶段会上下波动约28磅。该研究由英国“体重管理”网站slendex.com开展，共有三千名女性参加。

Slendex网站的简•麦克卡登说：“我们的情绪和感情状态会对我们的健康，尤其是体重产生很大影响。”