Inflation is turning into a severe problem for the U.S. economy. But this problem is caused mainly by rising food and energy prices, as any consumer who buys groceries and gas would have noticed. U.S. drivers paid almost double what they paid in the spring of 2020 when the COVID-19 pandemic broke.

That's confirmed by recent inflation reports, which show a divergence between inflation for all items and "core inflation," which excludes food and energy, including one released by the Bureau of Labor Statistics.

The Consumer Price Index for All Urban Consumers jumped 0.8% in November on top of 0.9% in October. For the last 12 months, the all items index increased 6.8%. That's well above the Federal Reserve's 2% target and the highest inflation rate since 1982.

That's why the situation is quite different when the Core CPI, which excludes food and energy, rose at 0.5%.

Here are two quotes from the BLS report:

"The food index increased 0.7 percent in November after rising 0.9 percent in both September and October. The food at home index increased 0.8 percent in November as all six major grocery store food group indexes rose; this was the third consecutive month that all six increased. The indexes for other food at home and for fruits and vegetables both increased 1.0 percent in November. The index for meats, poultry, fish, and eggs rose 0.9 percent in November."

"The energy index rose 3.5 percent in November after rising 4.8 percent in October. The gasoline index rose 6.1 percent in November, the same increase as the prior month. (Before seasonal adjustment, gasoline prices rose 2.8 percent in November. The electricity index increased 0.3 percent in November after rising 1.8 percent in October. The index for natural gas rose 0.6 percent in November following a 6.6-percent increase the prior month."

Food and energy are usually the most volatile components of the CPI. Both items are affected by weather conditions and supply interruptions due to transportation bottlenecks and other supply-side frictions. However, these factors aren't one-sided, meaning that they can move in the other direction, helping ease food and energy inflation.

That's why market analysts and the Fed focus on the PPI, excluding food and energy, which is a better indicator of the inflation trend.

Still, there's some riddle regarding the high gas prices. Gas is made mostly out of oil. Therefore, gas and oil prices must be moving in tandem. Gas prices must go up when oil prices go up and come down when oil prices go down. But the relationship between the two variables seems to be asymmetric. Gas prices follow oil prices at a faster rate up and at a lower rate on the way down. Crude oil dropped 12.10% last month, while gasoline has fallen 9.44%.

Experts attribute the asymmetric movement in gas prices to a temporary mismatch between demand and supply, due to time lags.

"Retail gasoline prices lag behind both RBOB and crude oil futures due to the longer supply chain link from refineries to the jobbers who distribute gasoline to gas stations," said Campbell Faulkner, senior vice president and chief data analyst at OTC Global Holdings. "As prices of both RBOB and crude oil have declined over the past few weeks due to Omicron fears, drivers have begun to impatiently seek relief from the drastically higher gas prices vs. one year ago. Lower prices are coming, but often lag a few weeks behind in the supply chain as gas stations will charge higher prices since they purchased their fuel supplies at higher prices in the past."

Shaya Sheikh, an associate professor of management and marketing studies at the New York Institute of Technology, provides further insight into how this happens. "Private oil companies can theoretically increase domestic production. However, it takes months to catch up with the increased demand. This is because private oil companies do not have enough spare capacity to ramp up the production instantly, and the process of surveying, drilling, refining and distribution take months."

Hopefully, they are right, as energy costs take a big chunk of consumer budgets, especially those with lower incomes.