Coffee is a natural laxative you know. It hasn't actually been proven 100% but it makes sense because it has the same effect on so many people- no matter what kind of coffee they drink (even decaf). For example, while my dad only drinks black coffee I drink it with milk and sugar and it has the same effect on both of us. There is a lot of speculation around this as it hasn't been proven which part of coffee promotes bowel movement- is it just the caffeine or the drink in a whole etc. As for milk, it will upset your stomach only if you're lactose intolerant (or it's too cold, you drank it too fast etc.).
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@xvarnah No comment
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