Comments
There's very strong empirical evidence that taxes reduce alcohol consumption (price elasticity is about -0.5, so a 10% increase in price reduces consumption by 5%), and the evidence that alcohol harms health is well-established enough that I won't belabour the point
It's probably also cost-effective. Rough rule of thumb is that policy interventions are highly cost-effective due to large scale of impact (policy has national level reach, while is hard to beat), and low cost per capita (particularly due to leveraging less impactful government spending). GiveWell estimates that alcohol policy may be more cost-effective than its top charities, and Charity Entrepreneurship estimates that it's potentially competitive with GiveWell top charities. Uncertainty is very high, of course.
The other posters have also rightly pointed out the conflict-of-interest reasons you should distrust this Snowdon fellow, but also the fact of the matter is that the scientific consensus is what it is for a reason, and even without conflict-of-interest reasons you shouldn't put too much stock in what some rando says over what experts as a whole say.
I expect there is some variability, the author in this piece focuses on alcohol, which I don't know that much about, but for "Reduce unhealthy diet" (Objective 3, page 10), CEARCH did a report here, which relates to WHO's best buys (if not quite exactly matching their specified intervention), and found it to be "49,419 DALYs per USD 100,000"
For best buys in education, I recommend Rachel Glennester's 80,000 hours podcast episode, where she praises the best buys, but also criticises how education spending is done
She has a second episode, which also touches on best buys
P.S. I'm not sure why this post has two disagree votes - seems like a perfectly valid forum post to me