Three-quarters of adults support a ban on junk food advertising before the 9pm TV watershed, according to a new poll.
The survey of more than 1,700 people, for Cancer Research UK found 74% would back a ban while 55% also want a tax on sugary drinks.
Almost seven out of 10 (69%) said there should be cuts to junk food advertising online while 66% want cuts to price promotions on junk food, such as buy-one-get-one-free deals.
Meanwhile, 82% of those polled said they thought childhood obesity was a problem.
It comes after a poll for Diabetes UK last week found 75% of adults want food manufacturers to reduce the amount of saturated fat, salt and added sugar in their products.
The Government is due to publish its strategy for tackling childhood obesity in the next few weeks.
It has so far resisted calls for a tax on sugary drinks - as called for by campaigners including celebrity chef Jamie Oliver.
Current estimates for school-age children are that 14.7% of all their calorie intake is made up of sugar.
The main sources of sugar include soft drinks, table sugar, confectionery, fruit juice, biscuits, buns, cakes, pastries and puddings and breakfast cereals.
Soft drinks (excluding fruit juice) are the largest single source of sugar for children aged 11 to 18. They provide 29% of daily sugar intake, on average, for this age group.
A third of 10 to 11-year-olds and more than a fifth of four to five-year-olds in England are overweight or obese.
Obesity causes some types of cancer, Type 2 diabetes, heart disease and stroke.
Alison Cox, director of cancer prevention at Cancer Research UK, said: "Junk food is everywhere. Children are bombarded by advertising tailored to tempt them with pretty colours and cartoons which all influence the food they prefer.
"At a time when junk food is cheap and packed with extra calories, we need stronger action to help prevent children from choosing these foods.
"We want the Government to ban junk food adverts on TV before the 9pm watershed, put a tax on sugary drinks and enforce targets for reducing the amount of fat and sugar in food.
"Reducing obesity rates could save the NHS billions of pounds. And, ultimately, we owe it to future generations to reduce preventable disease caused by being overweight and obese."