Caffeine also contributes to water retention; as it’s a diuretic, it can dehydrate your body. When you’re dehydrated, cells hold on to water—and your fat cells hold on to fluids, which, on your bottom and thighs, makes your skin bulge out and look puffier and more dimply.

And if that hasn’t put you off the black stuff, bear in mind that it’s also no friend if you’re a PMS sufferer. That’s because caffeine increases sleeplessness, anxiety and tension, which are symptoms of PMS. A study of over 200 college-age women found severe PMS symptoms in 60 percent of those who drank more than four cups of caffeinated drinks a day. Coffee also causes your body to get rid of important nutrients, especially B vitamins, which are needed for energy, good skin and hair, healthy growth, and mood.
It gets worse. Caffeine also destroys calcium—one cup of coffee removes about six milligrams of calcium form your body’s stores. Experts have found that calcium is important in weight loss because it’s thought to help prevent fat storage and boost metabolism. (You can increase the calcium in your diet with skim milk, cheddar cheese, fish, sesame seeds and dried figs. Other good sources include steamed tofu and nuts.)

So how much is too much? How much caffeine are you drinking?
About 300 milligrams of caffeine a day is a “moderate” intake. One cup of instant coffee contains about 100 milligrams, tea has 30 to 60 milligrams per cup, and cola around 50 milligrams per can. So three mugs of tea per day plus one cup of coffee would give you almost your daily “allowance.”