It's always better to give no data (aside from leaving them with "we couldn't collect that data") than it is to give fake data because that fake data will be used against you just as often as real data would. Don't hand companies extra ammo to use against you, or think that you're safe just because they've written an incorrect assumption about you on the bullet. You're still going to be taking the hit.
This gives me the idea to add features to target specific types of advertisements and pages for clicks and visits. Actively try to use the data in your favor to convince whatever algorithm that you’re a healthy eater with an active lifestyle.
To your point, unfocused fake data can be harmful to the faker but it seems focused fake data can work against the collectors.
It really might in some ways, but it's risky. Nobody is using the data they collect on us to help us. They use it against us to help themselves. You could limit the harm caused by one system, but expose yourself to new harms by another. It's also a safe bet that faced with conflicting data, companies and their algorithms will favor whatever information they think would make them the most money. It's still worth considering though, especially if you can get privileged information on how a specific system is using people's data.
