The committee also called for a crackdown on the black market for weight-loss drugs, saying the lack of availability on the NHS had driven people to buy unlicenced products online.
It wants a public awareness campaign to warn about the dangers, along with a review to look at how better to regulate online advertising.
The MPs also criticised the wider system of weight-loss services, saying they were poorly designed and resourced.
They want people to have better access to diet and lifestyle courses and bariatric (obesity) surgery.
Moran said obesity should be treated as a serious health condition, like diabetes.
"People can spend their entire lives battling with their weight. We say the NHS should provide effective, structured support to beat obesity for all those who seek it. Instead, those people are repeatedly failed," she said.
Jack Doughty, of the Obesity Health Alliance, said people living with obesity were being "let down by a fragmented and overstretched treatment system".
"The reality is that the existing treatment services, from behavioural support to weight-loss medications and bariatric surgery, remain patchy and unequal."
NHS England said it was looking at ways to accelerate roll out weight-loss drugs, but was currently “rightly prioritising these treatments for those with the most severe and complex needs“.