Heyyyy there , I promise you low carb and juice cleanse isn’t the best option for calorie deficit!
Carbs help satiate you and give you energy (oats,potatoes etc… are complex carbs ) where as simple carbohydrates may not keep you as satisfied ( ice cream, potato chips etc….) focus on protein ( most filling macronutrient ) and vegetables ( high volume food ) to help keep you fuller
Having smoothies in moderation is ok like once a day with a scoop of protein powder is a fantastic snack when paired with a carbohydrate in the form of fruit and a fat such as 10g of peanut butter to help keep you energised.
Having sugar filled smoothies all day isn’t going to satisfy you and result in you over eating later in the day .