Consider it a snack. Eat less. Cookies are not good things. Cookies have only two purposes, to satisfy hunger and nothing else. The so-called monkey mushroom, high calcium, and commercial gimmicks are just that. If they really have this function, they can't be counted as food and non-staple food, but should be classified as peaceful products, which means they can't be sold casually.
In fact, the ingredients of food sold in the market are not very reliable, and it is also well-founded to say that it is junk food. Everything produced by large commercial factories for profit is always suspicious.
When, what to eat and what to do afterwards have nothing to do with whether you will be fat or thin. Whether you will be fat or thin is closely related to your physical fitness and genetics. As difficult as gaining weight, it varies from person to person. You won't know until you have tried it yourself. Of course, a reasonable diet can make you healthier.