A quick quiz for mummies and daddies. Which of these pairs of snacks are better for your little darling?

1. A bite of MacDonald's quarter-pounder with cheese? Or a Farley's Toddler's Own Mini-Cheese Biscuit?

2. A dark chocolate digestive? Or a Farley's Original rusk?

3. A bite of Cadbury's Picnic bar? Or a spoonful of Kellogg's Crunchy Nut Cornflakes?

4. A packet of Walker's cheese and onion crisps, or the same weight in Tesco's Special Flakes breakfast cereal?

You probably didn't have much trouble with that. Obviously the naughty snack choices are better for a little 'un - there's less saturated fat, gram for gram, in the quarter-pounder, less sugar in the digestive and the Picnic bar, and much less salt in the crisps.

This all comes from new reports by Sustain's Children's Food Campaign and Which?. They also pointed out that Morrison's Choco Crackles, Kellogg's Coco Pops, Moons and Stars, Frosties and Ricicles are 37% pure sugar - indeed they contain about as much per 30g serving as a Cadbury's chocolate Flake.

OK, so you're not surprised. It does boggle one's cells, though, the way these food corporations have the cheek to trumpet their commitment to children's health. "We're on a journey to make sure we always make good food your family can eat at every mealtime ... working closely with the Food Standards Agency and Government health departments on healthy eating issues," says Heinz, who own Farley's. Some journey. And Heinz have a page on their site devoted to the problem of overweight six-year-olds and obese 15 year olds – where Heinz admits and profusely apologises for the role its played in Billy Bunterising the nation.

Actually Heinz doesn't – Heinz blames the parents. We should exercise our brats more and tempt them to eat greens by adding Heinz Tomato Ketchup and Heinz Salad Cream, it says. The sad thing is, some of us will. We trust them. And then we'll become the subjects of one of those specialist Daily Telegraph human zoo pieces, like this one, where "Britain's fattest mother" admits to raising her eight-month-old triplets on fast food. But that now seems not to be such a bad idea.

Still not shocked by the food corporations? OK try this. A bowl of Kellogg's Frosties – which, you may have noticed, is marketed at children, especially those who like tigers - contains 37g of sugar, about 7 teaspoons, in 100g. This is nearly half the entire recommended daily intake of sugar for a 5-10 year old (my 10-year-old Frostie-fan eats about 80g of the cereal in a sitting, when he can get them).

In 2004, after criticism from the government, Kellogg's promised to cut the sugar content of Frosties and introduced a new "reduced sugar" version, a mere 25% sugar to the standard 37%.

But where are Reduced Sugar Frosties now? All eaten up, probably by Tony the Tiger. They went out of production last year.

But don't worry. Kellogg's is taking steps, "because nothing's more important in life than your health and wellbeing". The website boasts: "We've teamed up with the Government's Change4Life initiative to promote a balance of eating well, being more active and therefore living longer." Still not surprised? Nor me.