You might be able to overlook your potato chips, cookies or bagged carrots showing up in smaller packaging at the grocery store, but you can’t ignore your receipts.

In May, a “thrifty” family of four spent an average of $612.70 on food prepared at home, according to the U.S. Department of Agriculture. That’s an increase of 4.6 percent over last year.

But the thrifty family’s monthly grocery bill pales compared to the $1,209.20 spent last month by families on a “liberal” budget, the USDA says. That’s an increase of 4.4 percent from 2010.

And you’ll continue to pay more for groceries this year — mostly, the USDA says, because of rising energy and agricultural prices and increased demand for food around the world.

Even couponers are feeling the pinch. Michelle Atwood, who runs the shopping website IheartPublix.com, says big coupons, like 50 cents off one product (which could double to $1) are becoming more scarce.

“Now we’re looking at 45 cents off three,” Atwood says. “I used to be able to get a box of fruit snacks after coupon for definitely under $1. That doesn’t happen anymore.”

Larry Peterson, who created MyGrocerySpy.com, says he’s noticed shoppers changing their habits to cope with rising prices.

“We’re seeing that people are tending to buy less than they have in the past,” Peterson says. “But they tend to shop a little more often.”

Instead of stocking up in heavy quantities on meat and produce, shoppers are buying them at more regular intervals, he says. He suspects the more frequent shopping is to hit sales at one or more stores.

Whether you’re using coupons or not, buying in bulk or shopping multiple times a week, Atwood and Peterson have tips on how to save even more at the grocery store:

Atwood: Make a menu based on what’s on sale. “You can easily save 50 percent by just shopping the sales.” She says people run up their grocery bills quickly by deciding to cook whatever they have a hankering for — say, a rib-eye steak for dinner — when it’s not on special.

Peterson: Shop on Thursdays — the day by which most metro Atlanta grocers have released sales in their circulars. That way you can compare sales across stores. “It’s the first day that most stores have their meat department sales. It’s also the best time for freshest produce because it’s usually stocked on Wednesday night. So you get the optimum pricing as well as the freshest produce.”

Atwood: Use what you’ve already purchased. “Plan your meals on what you have in your pantry and your refrigerator and supplement with what’s on sale that week.” She says many people ignore the rice, pasta or other staples stocked up in their cabinets. “You bought it for a reason — make good use of it.”

Peterson: Get your nose out of your list and keep your eyes peeled while shopping. Or you can use a site like MyGrocerySpy.com to get the scoop on sales that weren’t made public. “We find that a lot of the advertised deals aren’t as big as the unadvertised deals.”

Atwood: Eat first. “It sounds like common sense, but a lot of people just don’t realize [how much they’d save] if they would stop going to the store when they’re hungry. Impulse makes those cakes look really good in the bakery at the time.”

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While food prices can fluctuate for many reasons, at the beginning of this year it was largely because of gas. High transportation costs had consumers paying dearly at the pump and at the grocery store. Recent figures from the Commerce Department indicate that wholesale food prices have dropped, and we could be seeing some relief at the register soon. Overall, we’re on track to see prices increase in five key categories for the whole of 2011, although the gains nationwide won’t be quite as high as what we’ve already seen since just last May, according to the U.S. Department of Agriculture.

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Meat, fish, poultry

5-6%

USDA’s projected price increases for 2011

Prices are up 8.3% from May 2010 to May 2011

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Dairy products

5-6%

USDA’s projected price increases for 2011

Prices are up 6.9% from May 2010 to May 2011

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Fruits, vegetables

3.5-4.5%

USDA’s projected price increases for 2011

Prices are up 2.3% from May 2010 to May 2011

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Fats, oils

6.5-7.5%

USDA’s projected price increases for 2011

Prices are up 8.5% from May 2010 to May 2011

Join the conversation online at blogs.ajc.com/atlanta-bargain-hunter. Our Deal Spotter section in Thursday’s AJC is full of great local deals. offers.