"Brazil in essence needs to become more like China, with its investment growth, and China needs to learn from Brazil in how to support consumer spending," said Capital Economics' chief emerging markets economist, Neil Shearing, in a pan-EM report.
Growth has slowed in both the EM giants, as the impact of euro zone woes and a sluggish U.S. economy is felt in countries with previously robust economies. However, Shearing said that Brazil's and China's difficulties were largely rooted in country-specific, but contrasting, problems.
"For Brazil, the issue is that consumer spending, which for years was the driver of growth, can no longer continue to increase at rapid rates," he said.
Shearing noted that the Latin American powerhouse has one of the lowest investment rates in the emerging world, at under 20 percent of GDP. In comparison, investment accounts for nearly half of GDP in China, and 35 percent in India.
"Brazilian households spend roughly a fifth of their income servicing debt – far more than overleveraged U.S. households did before the financial crisis. This debt burden has understandably started to take a toll on their spending," he said. U.S. consumer debt servicing reached 14 percent of income in 2007, the peak of the housing boom.
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Brazil suffered a minor bank run last weekend, sparked by false rumors that the country's social security fund, the Bolsa Familia, was to be canceled. Economists such as Shearing viewed the panic as symptomatic of a consumer credit bubble.
"Credit cannot continue to be a driver of Brazil's growth. Banks like Caixa bank have been lending massively to the housing sector and there is evidence of a housing bubble. Defaults are on the rise and consumer confidence is declining. What we are seeing is credit-fueled growth starting to reach its limits – it is unsustainable," Shearing told CNBC on Tuesday.
In Thursday's report, Shearing said low rates of investment versus consumption meant the Brazilian economy was suffering supply constraints.
"Looking ahead, it needs to rebalance away from consumption, and towards investment. But this will require structural reforms, in particular to raise domestic savings, which will prove unpopular, and are unlikely at least until next year's elections are out of the way," he said.
In contrast, over-investment remains a problem in China, in Shearing's opinion.
"China's new leadership has made a great deal of the need to push through significant economic reforms to reorient the economy towards consumer spending, in order to secure sustainable and strong growth over the medium term. But that is easier said than done," he said.
In a red light for those bullish on an EM-led recovery, Shearing forecast BRICs' slowdown in 2013-14 will knock half a percent point of global growth.
"Moreover, because this slowdown is due mainly to structural factors, it will not be reversed unless each country steps up reform," he said. According to Capital Economics data, emerging markets have been responsible for three quarters of global growth over the past five years, and now account of over half of global GDP.
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Shearing added that outside of the BRICs, there were still some positive growth stories in the emerging world.
"One region on which we are particularly upbeat is Africa. Here, rapid economic growth has been made possible by greater political stability… We are also optimistic on the prospects for much of South East Asia – including Indonesia and in particular, the Philippines. Elsewhere, we are also fairly bullish on the outlook for Mexico," he said.
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—By CNBC's Katy Barnato