The New Theory On Weight Loss: Your Bad Diet Has Damaged Your Brain

You’ve tried and tried to lose weight, but it just doesn’t happen. Or you lose a bit, then gain it back with a vengeance. Sound familiar? Recently, while reporting a story on 3 new supplements studied for weight loss, I had the opportunity to speak with nationally known obesity expert Louis Aronne, M.D., Director of the Comprehensive Weight-Control Program at New York-Presbyterian Hospital /Weill Cornell Medical Center. According to Aronne, scientists are finally finding answers to the mystery that has stumped them for so long: Why do some people seem to find it impossible to lose weight, despite numerous serious attempts to get slim using diets and exercise? And what they’ve discovered might surprise you: Years of eating – and overeating – the typical American diet actually changes the brain. More specifically, it damages the signaling pathways in the hypothalamus, the part of the brain that regulates metabolism.
 “The evidence is quite convincing – eating fattening foods causes inflammatory cells to go into the hypothalamus,” explains Aronne. “This overloads the neurons and causes neurological damage.” A groundbreaking study in the British Journal of Nutrition published in February, 2013 is one example of the kind of high-quality, on-target research that’s proving the theory of hypothalamic damage and thus paving the way to new weight loss strategies, Aronne says. A team of scientists at the University of Liverpool analyzed a body of research that included studies of different weight loss diets. What they found was that a diet high in saturated fat and simple carbohydrates sets in motion a chain reaction of “metabolic dysfunction” involving the appetite regulating hormones leptin and ghrelin. (Leptin’s job is to suppress appetite, ghrelin’s to increases it.) In addition, a fatty high-carb diet resulted in “alterations in structural plasticity” – i.e. brain changes.
 Over time, consuming too many calories from fat and simple sugars damages the nerves that conduct signals through the hypothalamus, affecting the function of leptin and ghrelin, and thus the body’s ability to regulate weight and metabolism, says Aronne. ”Because of this damage, the signals don’t get through about how much fat is stored.” In other words, your brain has gone haywire and you can no longer trust the messages it’s sending you about appetite, hunger, and fullness. “It’s like your gas gauge points to empty all the time, whether or not the tank is full,” says Aronne. “So you keep stopping for gas, and then eventually you start filling up gas cans and storing them in the back of your car because you’re so convinced you could run out of gas at any moment.” So What Does Work for Weight Loss? Change your diet, and change it fast. “It’s about biology,” Aronne is fond of saying. While some damage to the hypothalamus may be permanent, it’s possible to reverse much of it. “If less fatty food comes in, it reduces the rate of damage,” he explains, noting that it doesn’t matter so much which specific diet you follow, as long as it’s one that cuts calories, reduces fat, and reduces simple carbohydrates.
 Of course, there are lots of trendy diets, such as the Fast Diet currently making headlines. And there’s no reason not to try a new approach and see if it works better for you than the ones you’ve tried in the past. But work with your body, not against it, Aronne says, and the weight will come off much faster. But wait, there’s more. Retooling your diet to be rich in health-promoting foods can stop and even reverse the damage done by an unhealthy one. In the above-mentioned study at the University of Liverpool, the researchers also looked at the impact of omega-3 fatty acids, known to be beneficial to brain health. And sure enough, fish oil appears to modulate some of the negative effects of the saturated fats and carbs. What that means, in effect, is that switching to a healthy diet can heal the hypothalamic damage that’s playing havoc with your hunger and satiety cues. Not surprisingly, Aronne has authored his own diet book (with coauthor Alisa Bowman), The Skinny: The Ultimate Guide to Weight Loss Success (2010). It features lean meat, plenty of seafood, lots of vegetables and fruit, and unprocessed grains.
 There’s also more information on Aronne and his views on brain signaling and weight loss available on the Weill Cornell Medical College website. But here’s secret number two: Permanent weight loss takes time. Aronne is quick to point out that many of those who’ve dropped massive amounts of weight on The Biggest Loser have gained most of it back again within a year or two. Once again, science suggests the problem is that it takes time for the brain’s metabolic messaging system to heal. Weight Loss Medications May Help If you’re in the group of people who’ve tried (really tried) controlling your weight with diet and exercise, Aronne says it’s worth considering taking a prescription weight loss medication. Doing so can reset your brain to begin healing the hypothalamic damage.
The two new diet drugs that just entered the market, Qsymia (formerly Qnexa) and Belviq, have the potential to do this, Aronne says. “Qsymia supports neuropeptide Y, amplifying the signals that come from the hypothalamus,” Aronne says, adding that Belviq (lorcaserin) and the migraine drug Topamax also have a beneficial effect on brain signaling. In other words, these drugs at least partially fix the broken gas gauge. Along with being overweight comes insulin and leptin resistance, Aronne says. “When inflammatory cells go into the hypothalamus, they prevents leptin – which signals to the brain that the stomach is full from getting in,” Aronne says. Among other things, Belviq stimulates the effect of leptin, Aronne says. “We don’t know exactly how it works, but it’s possible the mechanisms are hypothalamic.
Belviq appears to amplify signals that go to the critical area of injury.” Now I know I’ve reported in the past on concerns about side effects from Qsymia and Belviq. Qsymia has been looked at for potential heart valve damage because phentermine, one of the two drugs in the combination, was part of the notorious Fen Phen diet drug combo that caused serious heart valve damage in the 1980s and early 90s. But from Aronne’s perspective, the drugs have been studied very thoroughly and these concerns are unfounded. And more importantly, the seriousness of the health problems – and the increased risk of death – associated with obesity outweigh the risks of the drugs.