As the saying goes, "don't knock it until you've tried it."
Eating vegan isn't deprivation. Once your tongue gets used to eating real food, you can't believe all the energy you have.
While walking in Recoleta this week, I discovered SPARAW at Rodriguez Pena 1714. This is the first "fast food" place I've found offering real food for delivery and take out. It's all 100% organic food for vegans! I talked with the owner (he speaks English) who said they've been open four months and have plans for more locations in the microcentro, Callao and Juncal, and Palermo.
Their specialty is a variety of raw organic fruit and vegetable juices in glass bottles made for detoxing. The make almond milk.
I bought the Croquetas de Mijo package with squash and waldorf salad with vinagret dressing that was exceptional for 150 pesos ($8). I carried it home in their reusable bag with logo.
We've been adopting a vegan diet for almost two years (though we are not strict vegans, now and then we eat other food socially) but this energy boost/burst people talk about never happened. Yes, we don't feel 'heavy' as when we used to eat dairy and meat, but it is either you came from a heavily unbalanced diet or we are doing this wrong.
We've been watching documentaries on Veganism mostly from the US (on Netflix) and my take is that Americans have a fat-sugar laden diet they notice the most change (in a country where having diabetes is considered 'an epidemic' and not the result of bad nutrition, and taking several drugs is the norm). Veganism documentaries from Europe are not that much sensationalist in that sense.
I think it's nice the Casa Rosada is promoting a healthy lifestyle. If you want to find more vegan places, you can check out https://www.happycow.net (they also have an app)