What's behind the food frenzy?

The ongoing food frenzy comes down to this: buy or be bought.

"Think of it as a Pac Man for companies," says Michael Silverstein, senior partner at the Boston Consulting Group. If you don't swallow someone else, they may swallow you.

Perhaps that's why even giant Tyson Foods got into the melee Thursday when it offered $50 a share — about $6.8 billion — in an all-cash deal to purchase Hillshire Brands, which makes Jimmy Dean sausage and Ball Park hot dogs. Earlier this week, Pilgrim's Pride offered about $6.4 billion for Hillshire. Never mind that earlier this month, in a possible move to thwart Pilgrim's Pride, Hillshire bid $4.2 billion for Pinnacle Foods.

Some major drivers behind the ongoing food fight are:

• Demand for growth. It's extremely expensive to create and grow new brands — particularly food brands. It's much cheaper to grow by purchasing a company with familiar brands. "They're looking to buy market share rather than build it," says David Lewis, senior vice president at the Astec Analytics division at SunGard Financial Systems.

• Desire to cut costs. When one company talks about "synergies" with another that typically means cost-cutting. The combined food companies can pay less for commodities, transportation and packaging, says Silverstein, "because they have more market power."

• Aim for cheap financing. Interest rates are so low right now that it's easier and cheaper to finance big deals with debt than at just about any other time, notes Gary Stibel, CEO of the New England Consulting Group.

• Lust for scale. Bigger food makers have more power with retailers and suppliers, Stibel says. "To hold on to your seat at the table with Wal-Mart, you'd better have scale."

• Opportunity to expand. Many food makers are eager to expand into adjacent categories "to build awareness across different areas of packaged food," says Farha Aslam, managing director at Stephens Inc.

• Desire to be defensive. Some food makers want their lead — or to stop certain competitors from gaining market share, Aslam says.

• Urge to merge. Amid the nation's estimated 13,000 food companies, there fewer than 1,000 that are true takeover, merger or acquisition targets, Silverstein says. Uniqueness of brand or product makes them targets. And the universe, he notes, is contracting.

• Need to feed egos. CEOs of major food companies know they'll be remembered for one of two things: the products they create or companies they acquire, Silverstein says. The latter is easier than the former.

• Chance to shine. For many consumers, protein, the chief food category involved in these current merger talks, is back on-trend, Stibel says. Now, for example, there are more nutritionally-focused offerings like antibiotic-free meats. "Protein is no longer the big, bad dude," he says.