It is not controversial to say that an unhealthy diet causes bad health.

毋庸置疑，饮食不健康对身体不好。

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The detrimental effects of an unhealthy diet and insufficient exercise are not limited to your body.

不健康的饮食和不充分的锻炼带来的有害影响并不局限于你的身体。

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An unhealthy diet will nullify the effects of training.

不健康的饮食会抵消锻炼的效果。

《牛津词典》

He says combining medical and culinary expertise allows him to help people recognize the cooking mistakes that make their diet unhealthy.

VOA: standard.2010.02.23

But he pointed out that statins would not affect all the negative effects of an unhealthy diet.

BBC: 'Give out statins with junk food'

The prevalence of diseases related to an unhealthy diet and lifestyle is also on the rise, the government said.

FORBES: Fat In China

Those who watch huge amounts of TV are also probably more likely to have an unhealthy diet and be overweight.

BBC: Can watching TV make you die younger?