Whole milk gives the richest texture at roughly 220 calories for a grande latte, with about 11 grams of protein. The standard 2% lands near 190 calories and remains the baseline most published figures assume.
Oat milk is the closest in body and lands around 190–220 calories depending on the brand's added oils and sugars — check, because 'oat' spans a wide range. Soy is typically 170–200 calories and keeps meaningful protein (around 10 grams). Almond milk is the lightest common option at roughly 100–130 calories, with a thinner texture and only 2–3 grams of protein.
Coconut milk sits between almond and soy for calories. The honest summary: choose almond to minimise calories, soy to keep protein, oat for texture, and dairy when you simply prefer it — the differences are real but they are tens of calories, not hundreds.