While the Fund's economic outlook report predicts short-term global growth to 3.9%, it highlights debt levels, trade policies, decreased labor participation and aging populations as risks to long-term growth.
They put the current global growth rate at 2.9 percent, and say this moment of good growth is the time to make changes in tax and other policies that will help economies weather inevitable future downturns.
The World Economic Outlook report released on Tuesday, said that India's growth projections of 7.4 percent for this year and 7.8 percent for next year remained unchanged from the earlier estimates.
The IMF projects the U.S. economy will grow 2.9 percent in 2018 and 2.7 percent in 2019, both up 0.2 percentage point, anticipating positive effects from major tax cuts and higher public spending by U.S. President Donald Trump's administration.
"Emerging Asia, which is forecast to continue growing at about 6.5 percent during 2018-19, remains the most important engine of global growth", the fund wrote.
"Once the cyclical upswing and United States fiscal stimulus have run their course, prospects for advanced economies remain subdued, given their slow potential growth", the Washington-based lender said.
The two Asian giants have seen their economic prospects brighten amid strong global demand for their exports and as their massive populations start spending, the International Monetary Fund said.
Speaking at a news conference, Obstfeld said the International Monetary Fund had run economic simulations about the impact of a far-reaching trade war that would include across-the-board tariffs of 10 percent.
"The medium-term growth forecast is also broadly unchanged at 1.6%, reflecting the anticipated higher barriers to trade and lower foreign direct investment following Brexit".
The IMF's revised USA forecasts includes the benefits of the tax cuts passed in December, as well as a $1.3 trillion spending bill. Latin America is forecast to expand 2 percent this year, up from 1.3 percent in 2017.
India is expected to outpace China, registering 7.4 percent growth this year.
"Over the medium term, growth is expected to gradually rise with continued implementation of structural reforms that raise productivity and incentivise private investment", it added.
But an unfolding trade war between the U.S. and China, the world's two biggest economies, could hurt global growth as both countries seek to slap protectionist tariffs that would dampen trade.
Global growth is seen stable at 3.9% over the current and next calendar years, nearly unchanged from 3.6% in 2018.