Dishing out burgers and fries slathered with melted cheese, "One Way Burger" is like any other trendy food truck in Riyadh. But it offers something rare -- the cook behind the sizzling hot grill is a Saudi.

In the once tax-free petro-state, which long offered its citizens cradle-to-grave welfare, blue-collar occupations such as cooking, cleaning and working at gas stations have largely been the preserve of foreign workers, who far outnumber Saudis.

But Saudis are increasingly taking on such "low status" jobs in a new age of austerity when gas is no longer cheaper than water, with the government trimming oil-funded subsidies and tackling sluggish economic growth and high unemployment.

"When I started this food truck two years ago many people said: 'Whatij You will sell burgers and sandwiches in the streetij You come from a big family and big tribe'," said Bader al-Ajmi, the 38-year-old owner of One Way Burger.

"People were surprised," he added, as a Porsche pulled up at the side of his truck to place an order.

Since Ajmi started his business, dipping into his personal savings, owning a food truck has become the trend du jour and attained a level of respectability. Working inside as a cook apparently still has not. Still, many Saudis, long reliant on the welfare state for secure and undemanding white-collar jobs, are embracing manual labour jobs. For the first time, a new crop of nationals are working as tea sellers and car mechanics.

Posh lexus-owners work as Uber drivers for spare cash. "Will Saudis ever work as street cleanersij" columnist Abdulhadi al-Saadi recently asked in the daily Saudi Gazette.

"Some people will look down at this proposal... They should know that nations only rise on the shoulders of their own people," he wrote. last December, residents of eastern Al-Ahsa region feted a handful of young Saudis who swallowed their pride to do another job long deemed dishonourable -- working at a gas station.

"There is no shame in this work," a gas station customer said in a Snapchat video.

"Prophet Mohammed used to work as a shepherd." - 'We don't work for us'

It remains unclear how many nationals have moved into blue-collar jobs but the trend defies a popular maxim among Saudis: "They (expats) work for us, we don't work for us." "Saudis are moving into jobs historically dominated by expatriate workers," said Graham Griffiths, senior analyst at the consultancy Control Risks.

"The social stigma surrounding certain types of manual or service-based labour has been strong, but economic necessity is pushing many to take such jobs regardless of their social status." Cultural attitudes to work are changing amid a major retooling of Saudi Arabia's lagging economy, with the country seeking to wean citizens off government largesse as it prepares for a post-oil era.

Nearly two-thirds of all Saudis are employed by the government, and the public sector wage bill and allowances account for roughly half of all government expenditure.

Saudi economist Abdullah al-Maghlouth said the new economy will push more Saudis to become plumbers, carpenters and tailors, jobs that were acceptable decades ago in the pre-oil boom era.

Meanwhile, the government's push to replace foreigners with Saudi workers -- a policy known as "Saudization" -- as well as a backbreaking expat levy are driving a huge exodus of expats, who hold 70 percent of all jobs. Official statistics show nearly 800,000 foreign workers have left the kingdom since the beginning of 2017, creating what business owners call a "hiring crisis".

An Indian diner said it was in trouble, unable to secure work permits for its South Asian chefs, leaving its expansion plans in limbo. The exodus has sent the rental property market plummeting and cities like Riyadh are dotted with empty storefronts and shopping malls amid slack customer demand.

Some businesses implementing "Saudization" also complain of a high rate of attrition and a displaced sense of entitlement among more expensive Saudi workers accustomed to different economic realities.

A manager at a refrigerator manufacturing plant that recently hired dozens of Saudi assemblers and technicians said a handful of them were found "sleeping in their cars during working hours".

Many companies are reported to be circumventing the policy by paying Saudi workers small salaries to sit at home, effectively creating bogus jobs in a malpractice termed "fake Saudization".

The contentious policy is not driving down joblessness among nationals. Unemployment among Saudis rose to nearly 13 percent in the first quarter of this year.

The challenge, observers say, is not just to create more jobs for Saudis but also to convince citizens to take them.

Flipping sizzling slabs of meat inside his food truck, Ajmi said in the early days his business was a one-man show. He did everything from dicing vegetables to handling the countertop deep fryer. He has since hired two more Saudis and two Indian workers, but recruiting Saudis willing to do the late-night job -- from 9:00 pm until midnight -- remains a challenge.