alt Hacker NewsNote that the specified BMR is 2,900 in this article. If you are a heavier individual you tend to have a higher BMR.
A latte with semi-skimmed milk is closer to 100 (probably 125ish) than 200 calories in your example. A low fat greek yoghurt can be as low as 50 calories per 100g, so the 300 calories examples gives you 600 grams of yoghurt, quite a large portion.
The best way to hit a deficit though isn't to eat very little, its to eat satiating and/or high-volume food and add a small amount of exercise. For example potatoes will generally fill you up quicker than rice, pasta or bread for the same calories.
Also, BMR is not how much you need to eat, it's what you'd burn if you were effectively in a coma. RMR (resting metabolic rate) is what you'd burn if you were as lazy as humanly possible (one can dream), often 1.15xBMR, and actual output is typically 1.2xBMR for an extremely sedentary person.
Practically speaking if you do things with your life, like deliberate exercise, it'll be more like 1.3xBMR or more. Which means 3770 for a BMR of 2900 - a ton of food if you're not eating calorie dense things like e.g. ice cream.
If you were to eat, say, 1000 calories, and maintain activity levels (most people can't), youd be losing the better part of a pound of mass a day, and close to 50/50 muscle and fat.