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.

女性的體重變化受到很多因素的影響。有些人可能會認為，這是因為女性工作太忙沒時間健身。

也有一些人認為，這是因為女性禁不住辦公室巧克力機的誘惑。

但一項最新研究表明，真正的原因只有一個——那就是她們的愛人。

一項針對女性體重波動的研究顯示，愛情幸福與否是影響女性體重變化的最重要因素。

研究發現，女性在“戀愛初期”通常會控制飲食，這一階段她們的體重會下降5磅。

而在進入第二個階段即“舒適期”后，安逸穩定的生活會讓她們放松下來，同時體重也會隨之增加。

到了結婚籌備期，女性的體重又會減掉幾磅；而生了寶寶后，她們的體重又會大增，只有等到“再造期”重塑美麗身材了。

研究顯示，女性的體重在這五個階段會上下波動約28磅。該研究由英國“體重管理”網站slendex.com開展，共有三千名女性參加。

Slendex網站的簡•麥克卡登說：“我們的情緒和感情狀態會對我們的健康，尤其是體重產生很大影響。”