BAD : There are two artificial lakes - one for swimming and one for fishing.
GOOD : There are two man-made lakes - one for swimming and one for fishing.
BAD : The city has suffered both natural and artificial disasters.
GOOD : The city has suffered both natural and man-made disasters.
artificial = not made of natural materials: 'I still prefer sugar to all those artificial sweeteners.' 'Most people look better under artificial light.'
man-made = made or caused by people, although sometimes having a natural appearance: 'This canal is the longest man-made waterway in the world.' 'It's hard to believe that these enormous caves are actually man-made.'
BAD : He managed to lose weight by eating artificial diet foods.
GOOD : He managed to lose weight by eating synthetic diet foods.
BAD : I am worried about taking artificial products into the body.
GOOD : I am worried about taking synthetic products into the body.
BAD : I never eat artificial foods.
GOOD : I never eat synthetic foods/food substitutes.
synthetic = not natural but made by a chemical process: 'Many old herbal remedies have been replaced by synthetic drugs.'