When it comes to their weight and health, most Americans say they are motivated to take action. Yet an equally large number don’t really understand how to make that action most effective – a finding borne out by the nation’s rising obesity rate.

That’s one conclusion to be drawn from the fifth annual Food & Health Survey on consumer attitudes toward food safety, nutrition, and health, conducted by the nonprofit International Food Information Council Foundation (IFIC). The sampling of 1,024 adults took place over a two-and-a-half-week period in April and May.

A whopping 77 percent of respondents say they are trying to lose or maintain their weight, yet only 19 percent say they are tracking calories. Among all respondents, only 12 percent were able to accurately estimate the number of calories they should consume in a day.

Still, Americans are making dietary changes to address weight and health concerns: 69 percent say they’re changing the amount of food they eat, and 63 percent are changing the type.

Sixty percent also say they are engaging in physical activity to lose or maintain weight. However, 77 percent – the same percentage who are trying to manage their weight – are not meeting the government’s physical activity guidelines, notably the recommendation to include strength training, and roughly a third of Americans perceive themselves to be sedentary.

More than half of Americans do not consciously monitor the calories they consume and expend, although 62 percent attempt to make some adjustment to food consumption in relation to physical activity levels on a regular basis. Yet 43 percent don’t know how many calories they burn in a day, or offer wildly inaccurate estimates (for instance, 35 percent put the figure at 1,000 calories or less).

“Even at the highest level of government … there’s a significant focus on an overweight and obese population, with an emphasis on reducing the amount of calories in the diet and increasing physical activity,” says Marianne Smith Edge, R.D., a senior vice president at the IFIC Foundation, citing the White House’s “Let’s Move” campaign and the dietary guidelines at MyPyramid.gov. “But first people need to understand the role that calories play.”