Should taxation be combined with subsidies making fruits, vegetables and lean meat especially cheap? Will it actually improve diet or simply change it? And who will be affected? The truly overweight? Or the poor?

“What you have is a search out there for the best mix of ways to alter behavior,” said Dr. João Breda, the program manager for nutrition, physical activity and obesity at the World Health Organization Regional Office for Europe, which will issue a report on the subject soon. “And you have it coming from governments of all kinds, governments from left to right to center.”

But critics point out that the new interest in food taxes just happens to coincide with tough economic times in Europe. Some say the taxes are as much about raising revenues in a politically acceptable manner as they are about promoting healthy habits. And they worry that the taxes do, in fact, hit the poor the hardest.

One effort to raise taxes on saturated fat has already failed spectacularly. In October 2011, Denmark became the first country to institute such a tax, raising the price of meat, dairy, edible oils and fats, margarine and other blended spreads, among other items. Fans of the effort thought Denmark was perfectly positioned to make such a tax work, because it already had rigorous labeling requirements, an efficient administration and companies used to making these kinds of adjustments.

But barely a year later, Denmark gave up on the tax. In the end, experts say, the effort was undermined by political battles, pressure from the food industry and a population that quickly learned to go over the border to Germany to buy the products it wanted.

Yet many health officials say that even the failed attempts are a step forward in developing taxation strategies that will alter eating patterns on a continent that has had a rise in obesity rates in recent years, though they still run far below those in the United States.