Now, it's actually really normal to lose that much weight in the first week of a lifestyle change. From what I have read online, that weight is all the shit your body has been hanging on to from a really unhealthy diet. Things like water weight and gluten, etc...
However, it's still really cool to lose that much weight that quickly, and helps to motivate yourself to keep going.
Here's what I've been eating and doing to achieve that weight loss.
I eat a ton of vegetables. I don't even count calories for most vegetables. There's science involved some how that I am too lazy to post. Basically, the calories in vegetables are lower than the calories it takes for your body to digest them.
I eat roasted zucchini in garlic and onions until I am full as fuck. Or, I cut the zucs into spaghetti like strands and cook it with some natural pasta sauce. I only count the calories in the sauce if it has added shit like oils. I also devour an ungodly amount of eggs, and drink a lot of tea. The antioxidant benefits of the tea really helped my body flush out all that extra baggage my body was hanging on to.
I'll post a progress picture when I hit 10 lbs lost.