Since the Federal Reserve began aggressively hiking interest rates last year, economists have been fretting that a US recession is on its way. 

But the stock market has continued to defy expectations, and a string of positive economic data has eased the market's fears of an immediate downturn. 

Top economist Steve Moore is urging caution, though – warning the economy is not as robust as it seems.

"It's an economy that is, in my opinion, very fragile right now and in a real financial tough spot – when people are losing money relative to the purchasing power that they have," Moore, former chief economist at the Heritage Foundation, told Fox Business Wednesday.

Moore sees high food and energy prices as the main threat to the economy's health, ahead of July's Consumer Price Index report, set to be released Thursday.

The CPI number will shed some light on whether the Federal Reserve's tightening campaign is still helping to slow price rises, after the central bank hiked interest rates at the fastest pace since the 1980s last year.

"I believe the inflation rate might even a little higher than some of those projections because I'm looking at what's happening in food prices, in energy prices – the oil price went well over $80 a barrel in recent days, and so when you see those energy prices rise, they reverberate throughout the economy," Moore said. 

The economist added that he believes inflation, which soared to four-decade highs last year but has rapidly cooled since, a "regressive tax", as it disproportionately affects the lowest-income households. 

Moore sees high inflation as the result the Biden administration's excessive spending, which he noted has added almost $2.1 trillion to the national debt.

Other economists, such as Nobel laureate Paul Krugman, believe massive food inflation has been driven by Russia's invasion of Ukraine, rather than Biden's fiscal policies. 

"Russia may be the only government able to have much impact on world food inflation; we would definitely see some relief if Vladimir Putin called this invasion off (which he won't)," Krugman wrote in a New York Times op-ed Tuesday.