Not only does fast food tend to be unhealthy, but some of its ingredients are downright addictive. Here’s how to kick the habit.
The first time a clerk at McDonald’s offered to “supersize” his meal, Morgan Spurlock enthusiastically agreed, then trotted back to his car and wolfed down a giant burger, fries and soft drink. He soon felt queasy, and minutes later, this unhappy meal came back up. Nonetheless, he continued to eat three daily meals at McDonald’s as part of the monthlong experiment that became the hit documentary movie Super Size Me.
By the end of the month, he was 24 pounds heavier and his health was rapidly declining. Interestingly, he also was craving the same high-fat, high-sugar, high-carb meals that once made him sick.
“At the beginning of the movie, the food was clearly toxic to his system,” says Mark Hyman, MD, author of UltraMetabolism: The Simple Plan for Automatic Weight Loss (Scribner, 2006). “But toward the end of the movie, he didn’t feel right unless he was getting that same food in regular doses. He was irritable, anxious and depressed when he wasn’t eating it because he was going through physical withdrawal.”
Spurlock’s case was so dramatic that many nutrition experts now use his movie to drive home a salient point: Not only is much of the fast-food menu unhealthy, but it can also make an addict of you.
The Fast-Food Fix
When most people refer to physical addictions, they’re usually talking about alcohol, cigarettes and drugs. But research now shows that some of the ingredients in fast foods can have a similar addictive effect. The iconic fast foods — big burgers, overstuffed burritos, fried chicken, fish sandwiches, French fries, soft drinks and milk shakes — are loaded with sugar, highly processed carbs, saturated fats and trans fats. And those are just the ingredients we know about.
Like thousands of other food additives in our nation’s food supply, many of the flavor- and texture-enhancing ingredients in fast food have not been tested, says Hyman. “The exact mechanisms of neurologic injury are worked out only for a few ingredients, such as monosodium glutamate and aspartame, which are excitotoxins that stimulate the NMDA receptors in the brain. But an analysis of the Coronary Artery Risk Development in Young Adults (CARDIA) study, published in the Lancet in 2005, showed clear behavioral effects from food additives that indicate an addictive effect,” he notes.
“Fast food is often a perfect combined-delivery vehicle for all those elements in the food supply chain that are the most addictive,” says David Katz, MD, MPH, director of the Yale Prevention Research Center and coauthor of two books on food and diet, including Dr. David Katz’s Flavor-Full Diet: Use Your Taste Buds to Lose Pounds and Inches With This Scientifically Proven Plan (Rodale, 2007).
There’s the sugar, the fat, the salt, the refined carbs. But that’s not all: “The physiological dependence is furthered by the convenience, by the notion of a bargain, by the marketing campaigns. You feel deprived if you don’t get your fix,” says Katz.
One recent study by researchers at the University of Bordeaux in France found that caged rats overwhelmingly opted for sugar- or saccharine-sweetened water over cocaine when given the choice. Rat studies also have shown that eating high levels of fat can cause the ˙ brain to secrete a chemical that encourages more eating and discourages physical activity — and that one high-fat meal is enough to kick off this process.
“Both the sugar and the fat evoke brain chemicals called beta-endorphin and dopamine, which are also activated by heroin and cocaine,” says Kathleen Desmaisons, PhD, an expert on sugar sensitivity who pioneered the field of addictive nutrition. “When you put the fat and the sugar together, it’s more than one plus one. It has what’s called a potentiated effect, with a bigger addiction response, a bigger brain response. It’s like doing two drugs at once.”
Diners are generally drawn to fast-food restaurants — which account for about half of all restaurant revenues in the United States — by the convenience, the price and the skillful marketing, much of it aimed at children. Once you’re inside, it’s hard to choose the salads and other less-noxious menu items, because smelling the sugar and fried foods incites pleasure chemicals in the brain — the same chemical fix you get when eating these items.
After their meals, people tend to feel happy and satisfied. Later, however, their insulin levels crash, and their mood drops. They crave more of the same fat- and sugar-laden foods, and they only feel better once they eat them.
“The world is bright until the effect wears off,” says Desmaisons. “Then people feel grumpy and hopeless and inadequate until they have more. That’s the hallmark of addiction: They need more to get the same pleasant effect.”
So fast-food devotees tend to overeat to feed their addiction. Many experts assert that they also overeat because they’re not getting all the nutrients they require — even though they might consume as many calories in a single fast-food meal as they need to eat in an entire day to maintain their weight. The problem is that the foods they are eating are calorie-dense, but nutrient-poor: The most common fast-food ingredients offer almost nothing in the way of phytonutrients, for example, and tend to be very low in soluble fiber.
We know that the more foods become “food products” — far removed from the farms, fields and orchards where food naturally originates — the less nutritious they are. And the highly processed ingredients that form the base of most fast foods demonstrate that effect quite clearly.
“When they refine wheat into white flour, they take out 22 vitamins and minerals,” explains Elizabeth Pavka, PhD, LDN, a North Carolina nutritionist and wellness consultant. “They ‘enrich’ it by adding back only four vitamins and iron. If we do the math, we see that 17 vitamins and minerals are not present in white flour. When you feed the body all that sugar and fat and the food doesn’t even give you the nutrients you need, it’s a setup for poor health, obesity and all the major health problems we’re seeing in our country.”
Fast Food, Fast Weight Gain
It’s easy to understand how someone will gain weight if he or she frequently consumes 2,240 calories just for lunch (the combined caloric wallop packed by Burger King’s Tender-Crisp chicken sandwich, large fries and large chocolate milk shake). But it’s the nature of those calories, and not the calories themselves, that may be the greatest cause for concern. This particular lunch delivers more than 10 grams of trans fats, for example, which a recent study indicated may give both obesity and disease a major toehold.
Wake Forest School of Medicine researcher Kylie Kavanaugh, DVM, compared two groups of monkeys, one that derived 8 percent of their daily calories from trans fats and a control group that didn’t eat trans fats at all. She was looking for the impact of the trans fats on their cardiovascular health, but was surprised to find another adverse effect: The trans fat–eating monkeys gained three times as much weight as the control group, even though both ate the same number of calories each day. And much of the weight was belly fat, considered a risk factor for diabetes and heart disease. (For more on this dangerous fat, see “Anatomy of a Pot Belly” in the November 2006 archives.)
The lesson from this study? “People can’t go to a fast-food place and eat a typical meal there and then figure they can eat salad for the rest of the day to make up for it,” Kavanaugh explains. “That one meal is more likely to put weight on them than a meal cooked at home or without trans fats, even if it has the same number of calories.”
The CARDIA study also highlights the hazards of frequent fast-food dining. In this 20-year study, researchers tracked the habits of some 5,000 healthy young adults living in four American cities and found that frequent fast-food consumption was directly associated with changes in body weight and insulin resistance — a warning sign for type 2 diabetes. In fact, it was a greater risk factor than a sedentary lifestyle or alcohol consumption.
“The typical fast-food meal is designed to prey on the average person’s primordial preference for fats and salts and sugar,” says Mark Pereira, PhD, associate professor in epidemiology at the University of Minnesota School of Public Health and one of the study’s authors. “These meals may be pleasing to the palate, but they are quite risky for obesity, diabetes and cardiovascular disease.”
In addition to seeing their subjects’ actual increase in body fat, some nutritionists believe that people who frequently eat fast food gain water weight as the result of inflammation (and suffer other assaults to their health) because they are sensitive to common ingredients in the food. Without realizing it, these people suffer from what is called a “delayed food intolerance” to the corn, wheat, soy and dairy found in most fast foods. “This creates an inflammatory response in the body, which responds by holding water to dilute the effect of a toxic reaction,” says nutritionist Ann Louise Gittleman, PhD, CNS, author of The Gut Flush Plan: The Breakthrough Cleansing Program to Rid Your Body of the Toxins That Make You Sick, Tired and Bloated (Avery, 2008). “People have other symptoms with these delayed food intolerances, too, including fatigue and digestive problems. It’s a very big deal.” (For more on food intolerances, see “Lesson Learned.”)
Breaking a fast-food addiction is similar to breaking other addictions, experts say: Begin by admitting there is a problem, then make a plan to stop.
Gittleman believes the body needs to do some nutritional sprinting to get rid of the toxins present in fast food. In one of her earlier books, The Fast Track Detox Diet (Broadway, 2005), she calls for a week of highly conscious eating — lots of fruits and vegetables that maximize liver function; flaxseed and other foods that maximize colon function; healthy oils, small amounts of lean meat, and plenty of water, while avoiding excess dietary fats, trans fats, sugars, artificial sweeteners, alcohol and caffeine. A one-day juice fast and a three-day re-entry diet follow. (For more on Gittleman’s plan, see “Fast Track Liver Detox” in the May 2005 archives.)
Other nutritionists feel that fast-food addicts should taper off, rather than go cold turkey. Desmaisons suggests you begin by eating a daily breakfast that includes a good measure of healthy protein. The point is to fortify your body with good food and prevent the kind of hunger that sends you rushing for a fast-food fix.
Katz has a similarly pragmatic approach, especially with patients who say they can’t live without their fast-food fix. He allows them that fix — at least, for a while — but shows them how to make the rest of their diet healthier by reading labels and avoiding the sugar and fat hidden in other foods. Eventually, they can rehabilitate their taste buds and transition away from a fast-food preference.
“There are ways to satisfy just about any craving with foods that are good for you,” Katz says. “Our taste buds are very adaptable — if they can’t get the food they love, they learn to love the food they’re with.”