When did 'diet' die?

Yoghurt always seems to be discounted at the supermarket, so I buy whatever is on special but recently my partner has told me not to buy anything with artificial colours and sweeteners -- which seems to be increasingly difficult.

Like this yoghurt I bought last week. The 'Reduced' sticker covered most of the front but the bit I read said there weren't artificial colours or sweeteners. Yet when I got home my partner pointed out these ingredients have numbers. I protested that the yoghurt didn't call itself diet so it should've been okay and it was pointed out to me that diet is a word that's disappearing from packaging.

When did 'diet' die? It was suggested to me that since studies show diets don't work for long-term changes in eating habits, products are being marketed without the word diet. There's this suggestion you'll eat less if you eat the product with a claim to have bugger all fat and you're supposed to conclude weight will be lost. Bizarre.

And the branding "For me no fat"? It leads me to think that Yoplait are channeling Yoda and hoping the Force will assist with the marketing of this product!