Eating healthy has never seemed so complicated. You can barely open your eyes or ears – let alone your mouth – without getting a barrage of unasked-for advice from random food-group-haters, variously qualified nutritionists and the occasional orthorexic found at the end of a green smoothie straw. So it's nice to go to Mastic, which does healthy without the high horse, and lets you eat gluten-free or all-green or paleo if you like, but will also serve toast or milky coffee without a side serve of dogma about gut flora.

Mastic is a new cafe appended to Hellenic Republic; it's a George Calombaris operation. It's colourful and cheerful with seating at communal ping-pong tables (sorry, no, you can't knock out a quick game during lunch service) and appealing galley benches and nooks overlooking the street. Not-yet-blended smoothies wait for their moment, bright-eyed baristas make excellent coffee (with coconut or almond milk if preferred), and fermented beverages (kombucha or kefir) spritz in keen expectation.

Breakfast means bowls of It ingredients – chia, black rice, coconut yoghurt, goji berries – in exuberant combinations, or plated dishes such as a fabulous salad of grated vegetables and a clingwrap-poached egg with butter and herbs a la famous Spanish restaurant Arzak. It's good and the combination of egg and fresh veg is satisfyingly complete.

At lunch, there are wholemeal don't-call-them-bagels koulouri (try the terrific moussaka filling) and boisterous salads, such as green vegetables – raw, grilled, steamed – tumbled over herby yoghurt sauce.

Desserts are sweetened with stuff like honey, agave syrup, brown sugar (shock!), maple syrup and dates. The latter two play off in a raw Kit-Kat-sized bar with cacao, coconut, cashews, beetroot powder and chilli. It's full of vim, super tasty and, just like Mastic, offers healthy eating that's neither haughty nor ho-hum.

Rating: Four stars (out of five)