In the first paragraph, the article points out that people often fail to keep their New Year's resolutions to adopt healthier lifestyle. This example supports the paragraph's main idea that

Question

a. any effort to change, including making resolutions you don't end up achieving, can have a positive effect on your future accomplishments.
b. making a New Year's resolution is ineffective if you really want to change your lifestyle.
c. most people are incapable of changing their behavior for longer than a few months.
d. people who set goals in January are more likely to succeed in meeting those goals.

Answer 1

a. any effort to change, including making resolutions you don't end up achieving, can have a positive effect on your future accomplishments.