A magazine advertisement by the cereal manufacturer suggested the company's products could stop school bullying.

The advert showed an overweight boy with the caption: "Sticks and stones may break my bones but names could really hurt me."

Consumer Affairs Correspondent Nicola Carslaw: "Kellogg's said it had the support of anti-bullying groups"

The text went on: "One of the most common causes of bullying in school is being fat. And there are many deeply hurtful names associated with it....

"Of course a cereal breakfast like Kellogg's can't solve complex weight problems, but in its own way it can really help."

Among the complaints received was one from charity Kidscape, which said being overweight was not a common cause of bullying.

Kellogg's said it had the support of other anti-bullying groups and that it was suggesting a solution in a "responsible and positive way".

Mattie Alderson: The Kellogg's ad "trivialised bullying"

But the ASA disagreed and has told the company to change its approach.

Speaking on BBC Radio 4's Today programme, ASA Director General Mattie Alderson said the advert "oversimplified and trivialised bullying" and "exploited children's and parents' insecurities".

The authority had upheld the complaints because there was no evidence to support the advertisement's central theme that being fat was one of the most common causes of being bullied in school.

On the same programme, Dr Lynne Friedli of the Health Education Authority said that the answer was not to suggest that fat children or those who are being bullied should change their diet to address the problem of bullying.

Dr Lynne Friedli on the damage to children's self-esteem

This was suggesting that the problem lies with the child, she said.

"The answer is to actually tackle bullying and also to encourage within schools a much more tolerant and anti-discriminatory environment," Dr Friedli said.

Promising a miracle

In another case the watchdog dismissed complaints against a church that promises miracles.

The ASA said Peniel Pentecostal Church's advert, which described it as a "church where healing and miracles happen today", would not be taken literally.

The Authority warned evangelical churches to avoid promising physical healing.

ASA's guidance not divine, but in line with advertising code

But it refused to uphold the complaint made by a methodist vicar about the claims made by the Essex church.

Instead, it mentioned a previous advertisement by another church, which had claimed to have raised six people from the dead.

It said any similar boasts must be backed by "rigorous scientific evidence".

The ASA added that "before" and "after" pictures supplied by some churches would not meet this criteria.

A spokesman said: "Our copy advice team provide guidance that, while not divine, will keep advertisers on the right side of the advertising codes."

Shampoo complaints rejected

The BBC's Torin Douglas on the shampoo ad's "harmless fun"

The ASA also rejected more than 130 complaints about shampoo advertisements showing naked men and women washing each other's hair.

The advertisements, for Nicky Clarke's Sports shampoo, were captioned 'The Rules', instructing users to: "1) Remove clothing; 2) Remove partner's clothing," through to Rule 6: "Don't get carried away."

The ASA ruled that the subject had been delicately portrayed and showed the couples having harmless fun.