The brands are collectively spending more than ever before -- many are up 25 percent year-on-year on their ad budgets -- yet there was an 8 percent decline in sales in the first five months of 2014. The government's Change4Life campaign, which promotes healthier lifestyles, has been singled out as a leading cause of reduced consumption.
It's not just in the UK. Globally, Mintel forecasts, fizzy drinks sales will be down from GBP8.3bn in 2011 to GBP7.5bn this year.
On the other hand, however, InBev announced UK sales were up 13 percent, largely thanks to its Budweiser brand being the official beer of the World Cup and its Stella Artois brand sponsoring the Wimbledon tennis championship.
The government's attempts to make us rethink our lifestyles would not appear to not fall even, then. Fizzy drinks are down but booze is on the up.
Of course, it could be that Budweiser just improved its marketing during the World Cup. Coca-Cola was singled out in recent GlobalWebIndex figures which showed nearly a fifth fewer UK consumers (18 percent) realised it was a World Cup sponsor at the end of the event compared to when it began.
It's a good question -- but that would only account for one company. The truth almost certainly is that Mintel is right.
Personally, I'm not particularly bothered if Coke and Pepsi sell more sugar-laden fizzy drinks, but if I were on their marketing teams, I think I'd be listening to Mintel's advice.
I'm no saint -- don't get me wrong, I'm far more of a Budweiser swiller than a Coke or Pepsi slurper. The difference is that the alcoholic drinks industry has taken its responsibilities very seriously for decades now. There's the Portman Group to encourage responsibility among producers and many financially support the national Drinkaware programme. Hence, when you look at the side of a bottle of booze, there will always be a logo and an explanation of how many units of alcohol the drink contains.
It's not perfect, and the brands may often disagree with ASA bans on adverts that are construed as showing their drinks make people feel more confident or successful, but there is never a complaint, the brands accept a verdict and move on.
So perhaps Coke and Pepsi could drop "the challenge" between the two brands and come together to run campaigns with other rivals which, as Mintel suggests, draws attention to "healthier" fizzy drinks.
For an industry's that's lost nearly a billion pounds worth of sales globally in the last three years, it couldn't exactly hurt, could it?
Coca-Cola is already doing this individually with its GBP20m campaign to get a million people more active by 2020 through its Coca-Cola Zero ParkLives initiative. Couldn't this be built upon to work with other brands' sub brands to form "Lo-Cal Local" fitness and education programmes. Maybe a sugar cube with a tide mark showing how much, or little, sugar is in a particular can or bottle might make sense -- a common kite mark for sugar, like we have for alcohol units?
The carbonated beverages industry has dropped GBP800m sales in the last three years so, at the very least, you'd have to say it's worth giving it a go, wouldn't you?