Who are the most powerful people in the food world in America? For the fourth year in a row, we are attempting to answer that question. What kind of power are we talking about? The ability to make things happen, rewrite the rules, change the conversation, shift the paradigms. The people with power in the food world decide or influence what and how and where and why we eat. Their power is economic, legislative, sometimes inspirational. They're the agribusiness moguls who decide what crops to plant and how to harvest, process, and sell them. They're the heads of major food processing and distribution concerns and retail food outlets (that is, the people who actually put food on our tables). They're the scolds and nannies — and admirable consumer advocates — who tell us what we should and shouldn't eat and why, sometimes upending whole industries in the process; the key figures in the governmental agencies concerned with the economics and the safety of our food supply; the media stars and public figures who sway our food opinions and stimulate our appetites; the chefs and restaurateurs who introduce us to flavors and culinary ideas, and establish and maintain standards for the preparation and presentation of food. They're the journalists, in whatever medium, who report on all of the above.

America's 50 Most Powerful People in Food for 2014 (Slideshow)

Any catalogue of powerful people — and certainly any ranking of them in order of perceived power— is bound to be highly subjective. That doesn't mean that it has to be arbitrary. To come up with our list of The 50+ Most Powerful People in Food in America, our editors assembled an initial roster, based on research done gradually over many months, then added and subtracted, fine-tuned and developed. We read news stories, annual statements, editorial analyses. We consulted with experts in the various fields we cover. We had endless discussions and occasionally strenuous debates.

Our ultimate criterion was simply this: Is each person on our list capable, whether by dint of corporate station, media access, moral authority, or sheer personality, of substantially changing, improving, and/or degrading the quality and variety of the American diet or the way we think about it? By this measure, CEOs are often more powerful than culinary celebrities, which is why you'll find more of the former than the latter on our list.

Roughly 75 percent of our honorees were on last year's roster, but there are some new names, too — either fresh blood in charge of the same mighty organizations we included last year or entirely new entries. Some of the returnees moved up the ladder and some moved down. This might be because of new accomplishments (or because of What Have They Done for Us Lately?) or just because we're looking at them this year from a different angle.

As in the past, we've included a number of high-profile individuals — irrepressible chef–restaurateur and humanitarian José Andrés (#18); First Lady and dietary advocate Michelle Obama (#22); Chez Panisse founder and Edible Schoolyard apostle Alice Waters (#39); and prolific food writer and New York Times food politics columnist Mark Bittman (#42), to name but four — but they are interleafed with less familiar personalities. Among these are James P. Hoffa, general president of the International Brotherhood of Teamsters, whose members transport food all over the country (#6); Doug McMillion (#3), new president and CEO of Walmart — which is, among many other things, the largest grocery retailer in the world; Kevin Systrom, who co-founded Instagram and changed the way we (literally) look at food (#24); Steve Spinner, whose United Natural Foods stocks the shelves at Whole Foods and hundreds of other right-thinking food outlets (#30); and Bill Marler (#47), a leading food safety advocate and a personal injury lawyer who specializes in foodborne illness suits.

In a number of cases, it must be admitted, power accrues not to the individual we name so much as to the organization he or she commands. Anyone who won the top spot at Monsanto (Hugh Grant, #2) or Weight Watchers International (David Kirchhoff, #27) would make our list, as would whomever holds the restaurant reviewer's chair at the New York Times (Pete Wells, #14).

It should be stressed that this is not a ranking of our favorite people — of the people we consider to be most admirable or worthy of our attention. Yes, there are people we admire on the list, but the fact is that food policies and the food choices Americans confront are all too often affected by people whose organizations or philosophies we do not find admirable (they know who they are).

Choosing which men and women in the American food world to include on our list was difficult enough; arranging them in order of power was a far greater challenge. We're confident that we've come up with a pretty good list, though. What do you think? Did we omit anybody obvious, or give undue prominence to some food folk or not enough to others? Check out the slideshow and leave a comment to let us know.

Additional reporting by Dan Myers.