Big Fat Stress Attack

Sure, pressure can cause meltdowns, but it also makes you snack. Big time.

You can't take much more. It's 3pm on a hellish day that's already included beetroot stains, a confrontation with your boss and a guilt trip from your mum.

You need a pick-me-up, a way to make it through the rest of the day without exploding. You need a Kit Kat Chunky. Or a giant plate of hot chips with gravy. Or, OK, even the month-old bag of probably-stale pretzels that's buried at the bottom of your desk drawer.

If you've ever felt this way, then you sure don't need us to tell you that stress can make you gain weight. And you're not alone: in a survey of more than 1800 people conducted by the American Psychological Association last year, 43 per cent of respondents admitted to overeating or eating unhealthy foods in response to stress during the previous month.

And women were more apt to do it than men. Forget Cornetto therapy. Research has uncovered new information about the link between stress and snacking that can help you break the cycle - no therapist required. And once you find out how to fight the biological odds stacked against you, not only will you be more relaxed, the waistband on your jeans will be too.

Why cavewomen didn't wear Shapewear: stress, fat and Darwin

The word "stress" gets tossed around more than egg at teppanyaki. But in scientific terms, that headache-inducing, nerve-jangling feeling is your body's way of trying to maintain balance in the midst of threatening and fast-changing situations. Your body achieves that balance by releasing hormones. So whether you've lost your wallet or missed a period, your body deals with it in the only way it knows how: by signalling the adrenal glands to release the stress hormones cortisol and adrenaline (the docs call it epinephrine).

You're probably familiar with adrenaline's role as the fight-or-flight hormone: it gives you instant energy so needed that boost to fight predators. Today, it's still useful when you have to respond to a threatening situation.

The logic behind our need to feed under duress, however, is less obvious. After all, doesn't scoffing cupcakes only make you lethargic? For the answer, you need to get familiar with cortisol. This other stress hormone is released by your adrenal glands at the same time as adrenaline, but you usually don't feel its effect for an hour or so.

When you do, you know it - cortisol's sole function is to make you ravenous."Cortisol is one of the most potent appetite signals we have," says nutritional biochemist Dr Shawn Talbott, author of The Metabolic Method. Some research suggests it may interfere with the signals that control appetite (ghrelin) and satiety (leptin). Stress and cortisol might cause our brain to find more pleasure in sweets. And because cortisol can mix your hunger signals and suppress your brain's normal reward system, feeling tense may make you crave a dessert.

This was good back when we just burned through a ton of kilojoules fleeing a sabretooth and had to refuel. But now that stress is more about busy schedules than about outrunning ferocious beasts, our biggest threat is having our bums grow to behemoth proportions.

While it might seem stress weakens your willpower, the real culprit is cortisol. The reason you want chocolate instead of raw vegies when you're stuck in traffic is that cortisol demands the most readily available sources of energy: high-fat, simple-carb foods that your body can use quickly. That's why big bowls of pasta, chocolate bars and potato chips have gained comfort-food status - they're exactly what your body craves in times of trouble.

We're not the only animals who respond to stress this way. Studies show even mice gravitate towards fatty foods when they're ticked off. Researchers at the University of Pennsylvania, US, offered lab mice their regular food and, for a one-hour window each day, as many high-fat food pellets as they could eat. When the mice were stressed (researchers riled them up by exposing them to the odour of a predator), they scarfed as many of the high-fat pellets as they could in that hour, and ate even more day after day. Result: fat, angry little critters.

Why self-deprivation is actually a really dumb idea

The mouse study also suggests that women may be more sensitive to this particular effect of stress; there may be a biological reason your bloke would choose to zone out on the couch rather than raid the cupboards after a shitty day. Researchers found that when a single high-fat food pellet was buried in the creatures' bedding, the stressed-out Minnies were much more motivated than the Mickeys to dig up the yummy nugget - uncovering it in an average of 60 seconds, while males took more than twice as long. (In the interest of safety, please don't attempt to recreate this test at home.)

Researchers at Montclair State University, US, found that men and women's snacking habits also differ. A group of subjects were given puzzles, some of which were impossible to solve, then they were invited to snack on bowls of peanuts, grapes, potato chips and M&Ms. The women tended to eat more of a healthy snack when they were able to solve the puzzles but dipped into the chocolate more often when they couldn't. Men showed the opposite response, eating significantly more unhealthy snacks when they mastered the puzzles.

Lead study author Dr Debra Zellner attributes the difference to men and women's attitudes about "taboo" foods. Men tend to eat junk food as a reward - in this case, for having solved the puzzles. On the other hand, when female subjects (many of whom were on diets) got frustrated, they reached for snacks to make themselves feel better.

That's a bad idea in more ways than one. "The more you try to restrict your kilojoules, the more likely you are to gain weight," says neuroscientist Dr Cliff Roberts, a senior lecturer with London Southbank University, who studied 71 healthy female students who were enrolled in a nurse practitioner program. In the 12 weeks from the beginning of the term to exams, 40 of the women gained an average of 2.5kg. All were habitual dieters who had exhibited the highest dietary restraint at the onset of the term, and all had significantly high cortisol levels. Dr Roberts believes that the added stress of trying to maintain their weight while keeping up with their schoolwork created a vicious cycle: stress drove them to eat; then eating (and the weight gain that followed) stressed them out even more and they resorted to filling themselves up with comfort food.

Chronically elevated cortisol levels from prolonged stress can affect weight even more over the long haul. For one thing, cortisol encourages the body to store fat - specifically, in the abdominal region - rather than burn it. It's nature's way of ensuring resources are available for fuel when the body needs to perform life-preserving exertion or withstand famine. This makes even more sense when you consider abdominal fat has both a greater blood supply (so cortisol travels there quickly) and more receptors for cortisol. The hormone also slows the production of testosterone, which is essential for muscle building. Chronically low testosterone promotes loss of muscle mass, which can slow your metabolism.

Why you should drive yourself to distraction

Unless you join a monastery, you can't avoid stress or stop your body's automatic reaction to it. But don't start pumping out cortisol just yet. There's still plenty you can do. Try these easy tension-relieving strategies:

Give in The Montclair State University puzzle studies indicated that women tend to eat more unhealthy foods only when they are both battling stress and restricting kilojoules in order to lose weight. That clearly indicates, Dr Zellner says, that women should stop depriving themselves.

"Instead of viewing certain foods as "off limits", they should view them as things they can have occasionally," she says.

Try budgeting one or two small treats into your day instead of avoiding them entirely - that way, you won't risk going overboard when your willpower finally snaps.

Sleep Yes, this might sound like the last thing you're capable of when you're strung out, but here's a bit of news that will encourage you to get some zzzs: "A person who gets less than six hours of sleep can have up to 50 per cent more cortisol in the evening than someone who gets eight hours," Dr Talbott says.

Sleep deprivation also increases the amount of ghrelin (the hormone that triggers appetite) and decreases leptin (an appetite suppressor). You may not even need as much snooze time as you think: a study in the journal Sleep showed that seven or eight hours a night is sufficient and that anything less or more could lead to weight gain.

Wait Unless you're a member of Naomi Campbell's entourage, you probably don't live in a state of constant stress. If you only face isolated outbreaks of tension, like traffic jams or dentist appointments, chances are you can beat cortisol's effects. Like all hormones, it doesn't linger in your bloodstream forever, so if you can avoid stuffing yourself for the two to three hours it takes cortisol to leave your system, you'll be home free.

"Distraction can be a great strategy," says psychotherapist Karen Koenig, author of The Food and Feelings Workbook. "Reading a magazine or doing a hobby you enjoy, like knitting, can succeed where yoga might fail for someone who isn't a fan."

Get therapy Don't wait till your island holiday to book your next massage - studies have linked the occasional back rub to lower cortisol. In one such study, a 15-minute chair massage decreased hospital workers' cortisol levels by 24 per cent. In addition to reporting less job stress, anxiety and depression after their rubdowns, the workers solved maths problems faster and more accurately.

What better excuse to hit the spa at lunch after a crazy morning? You'll be not only more relaxed, but also more productive. Can't break away? Keep a handheld gadget, like the HoMedics Quad Extreme rechargeable hand-held massager, plugged in at your desk and knead as needed. Mmm...

Move At least 30 minutes a day of any kind of physical activity can help you conquer the negative effects of cortisol. "Being active is a great way to reduce cortisol levels," Talbott says. "In our studies, we see cortisol falling by 15 to 20 per cent from the start to the end of a six to 12-week diet, exercise and stress-reduction program.

He also suggests changing your approach to working out: instead of "steady state" cardio (a consistent pace that elevates your heart rate to the 60 to 75 per cent of maximum range but doesn't overly challenge), try interval training, which pushes you to your max in short bursts.

"Interval training can change hormone balances faster than steady-state exercise," Dr Talbott says. That includes boosting your testosterone, which helps build muscle and restore metabolism.

Try it for your next session: warm up for five minutes, then work your way up by doing a one-minute sprint followed by one minute at an easy pace, then two and two, three and three, and so on.