(CNN) -- Let's face it, sometimes there's nothing better at the end of a long day than a glass of wine.
But sipping much more than that can wreak havoc with your shape, and not just by adding hundreds of calories to your diet. Alcohol temporarily keeps your body from burning fat, explains integrative medicine specialist Dr. Pamela M. Peeke, author of the book "The Hunger Fix."
The reason is that your body can't store calories from alcohol for later, the way it does with food calories. So when you drink, your metabolic system must stop what it's doing (like, say, burning off calories from your last meal) to get rid of the booze.
"Drinking presses 'pause' on your metabolism, shoves away the other calories, and says, 'Break me down first!'" Peeke explains. The result is that whatever you recently ate gets stored as fat.
What's worse: "Research has uncovered that alcohol especially decreases fat burn in the belly," Peeke adds. "That's why you never hear about 'beer hips' -- you hear about a 'beer belly.'"
So can you ever enjoy a drink without putting on pounds? Absolutely, if you imbibe the right way.
In fact, large, long-term studies published in the Archives of Internal Medicine and International Journal of Obesity found that middle-aged and older women who drank moderately (about one drink a day) gained less weight over time than those who never imbibed at all; they were also less likely to become obese.
It's a complex topic, but Dr. JoAnn Manson, professor of medicine at Harvard Medical School and co-author of the studies, says that the moderate drinkers appeared to be more likely to compensate for the occasional drinks by taking in fewer calories from other sources and also tended to be a little more physically active. (In other words, they didn't get blitzed on margaritas, then dive in to a bowl of fried ice cream.)
What else beyond basic exercise and calorie-counting can keep happy hour from turning into hefty hour? Health magazine dug into the research and grilled the experts on how you can have your sips and jeans that still zip.
Rule #1: Always eat when you drink
While the Harvard research suggests it's wise to factor in those cocktail calories, it's actually more important to eat right than to eat less, the experts stress. Skimping on food in order to "make room" for drinks will only backfire and send you straight to the bottom of the candied nut bowl.
Here's why: Most cocktails are loaded with simple carbohydrates, "so during a night of drinking, people end up with soaring blood sugar, followed by a 'crash' that leaves them ravenous," says Dr. Jason Burke, an anesthesiologist and hangover researcher who runs a hangover treatment clinic in (where else?) Las Vegas.
You can help counteract that effect by nibbling foods that provide long-lasting energy. "Before you go out, have dinner or a snack with protein, fiber, and healthy fat," says Karlene Karst, a registered dietician and author of the book "The Full-Fat Solution." "They stabilize your blood-sugar levels without slowing down your metabolism."
Karst recommends Greek yogurt with berries, almond or hemp butter with an apple, or a protein shake. An added benefit of grabbing a bite beforehand, she says, is that that Pinot or appletini will be absorbed more slowly into the bloodstream, minimizing its diet-damaging effects.
In addition to revving your appetite, tippling also makes you lose your eating inhibitions ("I only live once -- I'll have the steak frites!").
"It temporarily impairs the prefrontal cortex, the smarty-pants part of the brain that allows you to think clearly and rein inimpulsivity," Peeke says. "So after a certain amount of alcohol (and it's different for everyone), you're going to feel yourself not caring and letting it rip with food and probably drinks." A cocktail (or three) can make you forgetful, too -- as in, forgetting that the Death by Chocolate dessert is not on your eating plan.
The trick is to have an easy-to-follow strategy in place before you take that first sip. Scout out the bar or restaurant menu ahead of time and note your picks on your phone. Then set an alert to remind you to order wisely -- that way you won't have to think too much (or rely on that alcohol-impaired prefrontal cortex!) to stay on track.
As with your pre-partying meal, go for something with fiber, protein, and a little bit of healthy fat to help control blood-sugar levels and make you feel satisfied, Karst says.
Rule #2: Know that some drinks make you hungrier
When it comes to waist-friendly cocktails, the simpler the drink, the better. Not only do the sweet-and-fancy ones tend to have more calories, but the additional sugar can make you even hungrier: Your blood sugar skyrockets higher than it does on beer, wine, or a shot of something, making the plummet (and the resulting cravings) worse.
And then there are the calories! Booze has 7 calories per gram, making it the second-most calorie-dense macronutrient. (That's just below pure fat, which has 9 calories per gram.) This means a measly 1.5-ounce jigger of vodka has almost 100 calories.
Mix that up with some club soda and lime, and it's a reasonable tipple, but when you start tossing together a whole bunch of different liquors -- whether it's a hipster fizz made with bourbon, elderflower liqueur, and house-made bitters, or a dive-bar Long Island iced tea loaded with vodka, rum, tequila, and gin -- it really adds up (to the tune of 300 calories, in the case of a Long Island).
Even simple mixed drinks like rum-and-Cokes and screwdrivers pack extra calories because of the sugary soda and juice. "So if you're going to drink, have something straight up and simple like wine or beer," Peeke advises.
Any wine or beer works, but to trim about 10 calories per glass, choose a rosé or white wine instead of a heavier red. A whole pint of a dark beer is around only 170 calories (compared with 195 for the same amount of regular beer) and may leave you feeling fuller than, say, Champagne, because it's so starchy and rich, Karst notes.
Vodka, gin, or bourbon with club soda and a twist are pretty good bets, too. Club soda is calorie- and sugar-free and dilutes the alcohol and its effect on your cravings. Avoid juices, liqueurs (which are sweet and syrupy), colas, tonics, and super-sugary bottled mixes like the ones for a lot of bar-made margaritas and daiquiris.
Rule #3: Stick to a drink or two, tops
One drink a day is the widely accepted definition of moderate drinking for women, but there's a misconception among some bar-hoppers that you can go without alcohol all week and save your seven drinks for the weekend.
"That's the worst thing you can possibly do for your weight," Peeke says. (And, of course, for your health.) "It has a much bigger effect than one drink a day."
When you down three or four drinks in one night, your body has many hundreds of alcohol calories to process before it can continue to break down food calories or stored fat.
Plus, all those drinks throw your blood sugar even more out of whack so you're hungry as heck -- and because you're tipsy, your prefrontal cortex is misfiring and you now have zero compunction about ordering the fried mozzarella sticks with a side of ranch (and keeping them all for yourself). The extra calories alone are enough to pile on the pounds; have four drinks every Saturday night and you'll be up about 10 pounds in a year.
Rule #4: Beware that gnawing, starving feeling the next day
The morning after poses a new diet challenge. As if a hangover weren't punishment enough, you're fighting cravings for large amounts of cheesy, greasy fast food. Part of the problem is that you're dehydrated (don't forget, alcohol is a diuretic), and that can make you feel even hungrier, Karst notes.
But that's not the only thing at play. "The body needs energy to resolve the effects of a big night of drinking, so it wants the richest source of energy it can find, which is fat," Burke says. "Also, greasy foods tend to settle the stomach a bit."
To avoid that: When you're out, drink a big glass of water for every drink you have. Then, before going to bed, have some more, along with a snack that is high in fiber and protein such as high-fiber cereal or oatmeal, Burke suggests.
"You'll get important nutrients into the body that were lost during alcohol consumption," he adds. "Plus, foods rich in fiber stay in the stomach longer, so you'll be less prone to hunger in the morning."
With any luck, you'll also be less likely to overdo it in the a.m., ensuring your figure won't have to pay the price for a night out.