Will eating/drinking/taking [whatever] make me lose fat?

As usual, there's a healthy dose of threads asking if whatever thing - be it supplements, 'fat burners', green tea, apple cider vinegar - will make a person lose weight or not.

Many of us have been doing this for long enough, or have enough background knowledge in physics, to know that the answer is universally 'no'. But when you're new to all this, these claims are seductive, and the fact they're peddled so hard throughout the media can make them seem quite reasonable.

So I'm putting this out there for those who are confused or in doubt or feel there might be something in any of these claims. Here are some general principles to help you judge:

1. No side effects = no effects
Any substance that changes the way your body works is a drug, and drugs have side effects. It's inevitable. If you change one thing, other things will change too. A well-chosen drug may have minimal side effects, or tolerable side effects, but they'll be there. It will also interact with other drugs, or certain conditions, in ways that could be harmful. If there are no warnings of side effects, interactions or contraindications, it means the substance is not changing how your body works - it's doing nothing at all. Real drugs have warnings, because real drugs have real effects.

2: If it worked, it would be dangerous
If green tea really made you lose weight without having a calorie deficit, it would be dangerous to take too much of it. It could make you underweight or malnourished. It would be dangerous for people with low body weights, the elderly, pregnant women. People would be getting hospitalised for taking it inappropriately. Governments would be regulating it and limiting doses. If that isn't happening, it doesn't make you lose weight.

3. Getting fat isn't an illness, it's normal
Behind a lot of the claims for 'miracle weight loss products' is the idea that getting fat is somehow a flaw in your body, due to an 'imbalance' or 'toxins' or some kind of problem with your digestion, and so if you can take something to restore your internal health, you won't be fat any more. Reality is the opposite.

A body that gets fat when overfed is functioning correctly and normally. It's effectively getting all the nutrition it can from the food you eat, and storing extra energy as it has adapted to do.

To interfere with this process ('make me lose fat'), you would have to either artificially speed up metabolism (which is dangerous) or cause malabsorption of nutrients (which is dangerous). There are drugs which have these effects, but they are regulated and controlled, because they can be very harmful if taken inappropriately. They do not work by restoring 'balance' or removing 'toxins'. They work by chemically distorting your body's normal way of working. Green tea and apple cider vinegar do not do this - and really, would you want them to?

I hope this is of some help. I have huge sympathy with people who have fallen foul of the misinformation that flies thick and fast on this topic, and I hope this helps to arm someone against the bogus claims which aim only to lighten your pockets and keep your body heavy.