Theresa May’s failure to take effective action on Britain’s obesity crisis is highly significant and, so early in her premiership, an ominous sign. Up to now, the new prime minister has enjoyed a rare luxury at the top of British politics – relative anonymity. She has been home secretary for ever, of course, and from failed immigration crackdowns, to her kitten heels, to her “nasty party” warning to the Tories, has made her mark on the national consciousness. But as leader, we still don’t really know who she is or where she’s going.

She’s had rising support in the opinion polls – she is now more popular in Britain than Boris Johnson – partly because of a vague sense of “fair play” that’s fallen to her, as a quiet remainer, to try to clear up the mess left by the upper-class Brexit Boys. It’s also because her initial mini-speech outside Downing Street about the importance of improving social mobility struck the right chord with many non-partisan, non-Tories.

The rest of the pro-May case has been mostly about negatives. She isn’t a flashy egomaniac. She isn’t posh, in the sense of seeming “entitled” to power. She doesn’t hang out at the parties of wealthy PR fixers or media moguls. She keeps herself to herself and gets on with the job. She is decisive and to those around her, notably loyal. I would go further and point out that behind the scenes she has been notably sisterly to younger female MPs from all sides, encouraging women to enter parliament.

But you can’t hold that kind of popularity, based on vague sentiment and generalised impression, for very long. Eventually you have to take decisions; and you will be judged on them, not on your decorum or sisterliness.

And so to the problem of obesity. Although Jamie Oliver has been the relentless proponent of government action to tackle the crisis of childhood obesity in this country – and he is very angry just now, rightly so – the tersest case for intervention is made on the Treasury website, defending its “soft drinks industry levy”, aka the sugar tax. “The UK has one of the highest obesity rates among developed countries , and it’s getting worse. By 2050, over 35% of boys and 20% of girls aged 6 to 10 are expected to be obese. The estimated obesity-related cost to the NHS is over £6bn.”

Jamie Oliver’s TED talk on obesity and food

A modest tax on sugary soft drinks is to go ahead, but the rest of the carefully assembled anti-obesity strategy has been ripped up. No more restrictions on advertising or promotional deals on junk food; what Jeremy Hunt promised would be a game-changer on this issue is now apparently just the beginning of a conversation.

The Tory MP Sarah Wollaston has little time for the new watered-down strategy, saying it “puts the interests of the advertising industry ahead of the interests of children… and misses the opportunity to improve children’s diets by reining in the saturation marketing and promotion of junk food”. Even some major supermarket chains, like Sainsbury’s, which would have welcomed a ban on 2-for-1 junk food deals, have complained that Britain now needs compulsory targets for the reduction of sugar across the food and drinks industry. Its chief executive, Mike Coupe, says: “Nothing less will work.”

So why, confronted by her first big choice, has May gone with the lobbyists for big business, rather than the public health lobby? Is it because she privately agrees with the man she fired so robustly, Michael Gove, that Britain “has had enough of experts”?

I’m sure she would say certainly not, that it’s all about jobs and the need for continued economic growth after Brexit. And certainly government ministers and officials were bombarded by industry predictions that interference with its God-given right to flog junk food to the lower orders would result in huge job losses and closures. But every measure of serious social reform has faced exactly the same protests.

All but the most thuggish libertarians know that the interests of business need to be balanced against our social needs

You come across the same anti-action arguments time and time again. First, they say it’s bad for business. In fact, obviously any action by government is by definition “bad for business”. Two, it is claimed that obesity isn’t really caused by sugar or junk food, but something (anything) else – lack of investment in sport, too much television, you name it. Three (and this is fundamental) it’s all just an excuse by government, which wants to get ever bigger, crush our liberties, and tell us how to live our lives.

All but the most thuggish libertarians understand that the interests of profit-seeking business need to be balanced against other social needs. Hence it’s against the law to pollute rivers, dump waste on beaches, employ young children, or push hard drugs. The arguments used against the obesity strategy are only slight variations of those used against the smoking ban.

Is May so frightened of presiding over a major Brexit-induced recession and losing the next election that she is giving business a free ride? If so, given the national mood, she’s making a serious mistake.