They say too many fizzy drinks can affect your concentration and can also interrupt your sleep, especially the ones with caffeine in.
The BMA says it might ask the health and education departments in the government to think about getting rid of vending machines.
One Norfolk school's already done just that.
And now state-run schools in New York, US, have banned sugary sweets and fizzy drinks from September.
They won't be able to sell anything thought to be unhealthy or fattening.