Ministers must introduce tough new measures to tackle childhood obesity, including controlling the "deep discounting" by supermarkets of unhealthy foods, MPs have said.
In a new report, the Commons Health Committee said the Government's childhood obesity strategy published last August does not go far enough.
MPs have previously made a series of recommendations to tackle obesity, but most of these were ignored or rejected by the Government, they said.
One recommendation was for strong controls on price promotions of unhealthy food and drinks but there was "no mention of price promotions" in the Government's strategy, the new report said.
Other recommendations included tougher controls on the marketing and advertising of unhealthy food and drink, but the strategy made "no mention of marketing and advertising".
Further proposals were also not acted upon, MPs said, including the labelling of products to show their sugar content in teaspoons.
There was also no mention of improved education and information on diet, or stronger powers for local authorities to tackle the environment leading to obesity.
One measure that was adopted - to lower the amount of sugar in food and drink targeted at children - is voluntary and the Government has not set out what "penalties or sanctions" will happen if food manufacturers do not do this, MPs said.
They are now calling on the Government to take stronger action, including reducing "the impact of deep discounting and price promotions on the sales of unhealthy food and drink".
They said industry representatives themselves have called for a level playing field in this area through regulation.
"Retailers who act responsibly on discounting and promotions should not be put at a competitive disadvantage to those who do not," they said.
They also called for measures to "reduce and rebalance the number and type of promotions in all retail outlets, including restaurants, cafes and takeaways.
"In our view this should not be limited to products which are high in sugar, but also those high in salt and fat. Voluntary controls are unlikely to work in this area and the Government should introduce mandatory controls."
MPs also said they agreed with Public Health England that confectionery and other less healthy foods should be removed from the ends of aisles and checkouts.
"We recommend an outright ban on these practices and call on retailers to end the promotion of high-calorie discounted products as impulse buys at the point of non-food sales."
While welcoming the new tax on sugary drinks, MPs concluded they were "extremely disappointed that several key areas for action that could have made the strategy more effective have not been included."
They also said the cost of the sugar tax must be passed on to consumers by companies in order to be effective.
Chairwoman of the committee, Tory MP Dr Sarah Wollaston, said: "We are extremely disappointed that the Government has rejected a number of our recommendations.
"These omissions mean that the current plan misses important opportunities to tackle childhood obesity.
"Vague statements about seeing how the current plan turns out are inadequate to the seriousness and urgency of this major public health challenge."
Public health minister Nicola Blackwood said: "We welcome the committee's recognition of the progress we have made in this area, delivering the most ambitious plan on childhood obesity in the world.
"It is backed by the soft drinks industry levy as well as the most comprehensive reformulation programme of its kind, anywhere.
"Voluntary approaches have been shown to be very effective, but as we have repeatedly said, we have not ruled out further measures if results are not seen."