Addiction is often defined [in scientific literature] as having two core elements: Reward and reinforcement (i.e. likelihood to seek repeated exposure).
Addiction in general is a sliding scale. With anything offering both reward and reinforcement being a potential candidate for addiction.
We need protein nutritionally but both the reward and reinforcement are lower than sugar. So if you wish to call protein addictive, you may be able to, but I'd still suggest it is further along the sliding scale towards the "less addictive" side.
Plus if we measure addiction purely by its negative impact on society, sugar addiction claims thousands of lives every year. I don't know how many (if any) lives are claimed by protein addiction.
It's really changed my perspective of sugar.
https://health.usnews.com/wellness/food/articles/2018-11-16/...
A news article in "US News" that cites three people isn't a "scientific consensus." In fact the article itself reference enough contradictory research to show that it couldn't be a consensus (the only "consensus" right now is that there is no consensus and it depends which measure you use to define it).
Plus their entire position boils down to this:
> The research shows, among other key differences, that while similar neuropathways are involved in both drug and sugar consumption, the brain changes that lead to needing more and more cocaine to get the same high aren't seen with sugar.
They're conflating addiction (i.e. habit forming behaviour) with something completely unrelated (biological diminishing returns for addictive substances). According to that definition very few things are actually addictive (which is the crux of this article).
Both the DSM and ICD have a ton of stuff in them that wouldn't fit that tiny definition: Gambling addiction, food addiction, sexual addiction, video game addiction, etc. In fact the majority of the listed addictions aren't according to this article and these researchers.
Second, there seems to be more subtlety to it than could ever be resolved by arguing semantics over vernacular terminology. For example, consider this angle: https://bjsm.bmj.com/content/52/14/910
And one of the dirty tricks our brains play on us is, a quick but short-lived mood bump is more salient than a constant improvement.
FWIW, for my purposes, "sugar" maybe has more to do with the blood sugar spike than chemistry. Mashed potatoes would count, insofar as, at least according to the tables I've seen, mashed potatoes have just about the highest glycemic index money can buy.