The "can be counteracted" part is the one I doubt. Of course if people were perfectly rational they just wouldn't consume sugar, but sugar is addictive and the human psychology doesn't have a simple off switch.

If it can be counteracted, it's only with measures that don't depend on individual choice.

Also for covid apart from old age the main risk is with all the same cardiovascular issues that sugar is a a causative agent for, so by decreasing sugar consumption we could probably lower covid deaths as well.

Maybe a tax on sugar like on cigarettes. One of the main reasons for our high sugar consumption is the food industriy's reliance on sugar to replace taste from proper ingredients. If sugar is more expensive than using quality ingredients the food industry would have a profit motive to move away from it.

On the private consumption side, I bought my 1kg of sugar about 2 years ago. If it costs 50€ to buy instead of 50 cents, I could still afford my birthday cake, but would be nudged to consume less.