Artificial Sweetners: No Panacea
Okay, you’re thinking. I’ll just make sure I minimize my consumption of high-fructose corn syrup by focusing on foods with artificial sweeteners. Not so fast. There’s some evidence that artificial sweeteners like aspartame (Equal), saccharin (Sweet ‘n’ Low), and sucralose (Splenda) may also increase setpoints in non-diabetics.
In one study, researchers fed two groups of rats sweet-flavored liquids for ten days.
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One got sugar-sweetened liquids while the other got liquids sweetened with sugar and saccharin. After ten days, both groups received a sugary, chocolate-flavored snack and regular rat chow. While both groups of rats ate about the same amount of the chocolate snack, those previously fed sugar and saccharin ate three times the amount of rat chow than those rats fed only the sugar-sweetened drink.
Scientists think that artificial sweeteners could interfere with our natural ability to regulate how much we eat
e
. It doesn’t change our drive for sugar (that’s always appealing), but it does increase the drive for calories.
As you learn how to become attentive to your body’s signals for hunger and fullness, stay aware of whether higher fat foods satisfy your appetite. Do you seem to need more than you would expect to feel full? (The previously mentioned caveat is true here too: Since leptin plays a role in long-term weight regulation, not just meal-to-meal satiety, your satiety level may not give you the full picture, though it’s a pretty good indicator.)
It’s quite complicated to figure out what really drives your eating behavior, however. High-fat foods are typically “forbidden” foods for dieters. If you hold onto the idea that “high-fat is bad” and deprive yourself, you make yourself vulnerable to what scientists call “deprivation-driven eating” and the usual brakes that stop eating stop working effectively. In other words, dietary rules—like the low-fat admonishment—may contribute to the over-eating that some people experience. Giving yourself permission to enjoy high-fat foods may just be the secret that supports you in enjoying them in a moderate and healthy manner.
High-fat diets may also lead to insulin resistance,
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which increases the potential for weight gain. Reduce the dietary fat, and insulin resistance reverses.
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Additionally, the body converts food fat into body fat quickly and easily, which also may contribute to higher weight in people who overeat: One hundred excess calories of ingested fat can be converted to 97 calories of body fat. One hundred excess calories of protein or carbohydrate, however, are converted to only 77 calories of body fat because more calories are burned in the conversion process.
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(If you don’t overeat, this imbalance may not exist since you probably won’t convert as many calories into body fat.)
Here’s another surprising fact: Some animal studies suggest that repeated and frequent exposure to fatty foods reconfigures the brain to crave still more fat!
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One study even found that fatty food can override whatever leptin signals do manage to get out. In this study, researchers force fed rats until they had gained a significant amount of weight, then injected leptin directly into their nervous system. The result? The rats continued to eat less of a standard rodent diet and more of the high-fat diet.
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There Is No “Free” in Fat-Free
In the past ten years, grocery store shelves have seen an explosion of fat-free and low-fat foods, all designed to play into our fears of fat. There’s only one problem: Reduce the fat and you reduce the flavor. To compensate, manufacturers dumped in plenty of flavor enhancers. Thus, most processed fat-free foods are filled with sweeteners (usually high-fructose corn syrup). That may boost your setpoint, leading to weight gain.
And how about this finding: One eight-month study found slashing the amount of fat from the typical 30 percent most Americans get to 15 percent enabled participants to eat an average of 120
more
calories and still maintain their body weight.
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While the evidence supporting the effect of dietary fat on weight is compelling, most of this research doesn’t distinguish between types of fat—which is really important and may explain some of the ambiguity in the research. For example, unsaturated fats (the kind primarily found in plant foods) trigger more leptin production than saturated fats (found mainly in modern animal foods) or trans fats (found in processed foods), which trigger barely any. High-fat diets are typically high in saturated and trans fats, which may explain why they do a poor job in activating your weight regulation system.
Within unsaturated fats are the monounsaturated fats, found in high amounts in olive oil and oils made from some seeds and nuts, polyunsaturated fats, like those found in vegetable oils, and a specific type of polyunsaturated fat called omega-3 fat, also found in high amounts in some nuts, seeds, and fatty fish. Monounsaturated fats and omega 3 fats stimulate the most leptin release (thus stemming hunger), followed by the other polyunsaturated fats, with saturated and trans fats trailing far behind.
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Given all this evidence about fats, here’s another interesting observation—the major source of saturated fat in our diet is meat. And meat consumption reached record highs in the 1990s. That includes red meat and poultry, both of which are high in saturated fat compared to other protein sources.
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Between 1909 and 2000, consumption of chicken quintupled from 10 pounds per year per person to 54 pounds; beef jumped 24 percent and pork jumped 15 percent.
Unmasking the Fat Myth: Doesn’t Fat Fill Us Up?
Most people believe that fat is the most filling form of food because it’s denser in calories (one gram of fat contains 9 calories vs. the 4 calories in a gram of carbohydrates or protein) and it keeps your stomach from emptying too fast. Yet research shows just the opposite when compared calorie for calorie to protein or to fiber-rich carbohydrates.
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Why? We can’t store carbohydrates or protein calories as well as fat calories, so they get used immediately or turned into body fat. However, we can store endless fat, and since it doesn’t need to be metabolized immediately, it provides a weaker satiety signal. Fat is also so calorically dense it’s easier to eat too much before your “I’m full” signal kicks in.
No one—especially me—is suggesting you eliminate fat from your diet. Not only are some types of fat necessary for survival and healthy functioning, but it’s clear that monounsaturated and omega- 3 fatty acids have a weight-taming effect through their effect on long-term weight regulation. Not surprisingly, these were the types of fats in greatest availability during the time of our Paleolithic ancestors—and those we get the least of in our modern diets.
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This fact may also partially explain the well-documented benefits of the Mediterranean diet: People in Greece get a higher percentage of fat in their diet than we do, but maintain lower weights and have less heart disease. Their diets are rich in the beneficial fats.
Fat is also important as the vehicle that delivers flavorful compounds in food to our taste buds, making foods much more pleasurable. And pleasure, as you’ll see in future chapters, plays an important role in making us feel content because it actually activates satiety sensors in our brain.
So instead of eliminating fat from your diet, consider becoming mindful of the types of fat you’re getting in your diet. You may want to experiment with increasing unsaturated fats and noticing the impact this has on your feelings of satiety and contentment. It may just be that this change leads to a greater sense of satiation and wellbeing—and is something you come to prefer. Remember, we’re all a bit different: Check it out for yourself!
Protein ... and the Meat Controversy
For all the hoopla around the high-protein diet craze, the gurus of this movement had one thing right: Protein is much more effective at filling you up than either carbohydrate or fat.
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If you were to go on a high-protein diet, you’d probably eat less at individual meals, and see a quick weight loss
in the short-term.
However, this form of eating has minimal impact on longer term signals. Eventually—over the course of weeks or months—you may be driven to take in more calories—or spend fewer calories—than if your diet were composed of nutrients like low-glycemic starches and mono-unsaturated fats that activate satiety signals. For this reason, high-protein diets are unsustainable—and the real problem comes when you stop the diet.
In fact, the link between protein and weight goes in the opposite direction than is trumpeted—larger people tend to eat more protein than those that are slimmer.
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Makes sense when you consider that high-protein diets are also high in saturated fat and low in fiber. Another problem is that even diets just a little high in protein (more than 10 percent of calories) can make you crave carbohydrates because of their impact on certain hormones.
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Yet the average American woman gets about 23 percent of her calories from protein; the average American man, about 18 percent.
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But wait, you say, sure that this time you’ve got me . . . didn’t our thin Paleolithic ancestors subsist on a high meat diet? Yes, you may be right (this is controversial).
But
. . . and it’s a big “but” . . . the meat they ate was very different from what’s available today. They subsisted on wild game, not corn- and soy-fed domesticated cattle. Meat from wild game contains about 2 to 4 percent fat and relatively high levels of monounsaturated and omega-3 fats compared with today’s grain-fed domestic meats, which can contain 20 to 30 percent fat, much of it saturated.
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Thus, in evolutionary terms the meat we eat today is a new food for us. To mimic the kind of (meat-based) diet our ancestors followed, we’d be better off concentrating our diet around unprocessed plant foods, using meat, if desired, as an accompaniment rather than the main attraction.
The research also shows that choosing plant foods over animal foods affects us in many ways other than weight, increasing longevity and reducing risk of heart disease,
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metabolic syndrome,
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and many other diseases. Despite the fantasy promoted by the Atkins camp and other supporters of meat-based diets, there is no evidence that it will get you thinner or healthier.
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Want to get the short-term, appetite-reducing benefits of protein without the negative long-term effects that may result from overconsumption? By having a little bit of protein with every meal, you are likely to notice that you will feel full longer. It will also temper the rise in blood sugar that results from the carbohydrates you eat with it, which is especially helpful if you feel a drop in energy after eating foods high in carbs. Plant proteins, like those found in vegetables and beans, serve this purpose well and come bundled with plenty of fiber and other great nutrients.
Drinks
Whether or not sweetened drinks affect weight gain is a matter of great controversy. A well-funded industry clouds the scientific analysis. When researchers analyzed 111 studies of beverages published over a four-year period, they found that studies entirely sponsored with beverage industry money were up to eight times more likely to result in industry-favorable conclusions than studies not funded by the industry.
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Take the industry-funded studies out of consideration and there is a strong correlation between soft drink consumption and heavier weight.
Makes sense that drinks play a role in our weight. For most of our evolutionary history, the only beverages we drank were breast milk and water. Because water has no calories, our bodies didn’t evolve to reduce food consumption to compensate for the drinks we were consuming. Though humans have been drinking wine, beer, fruit juice, and milk for thousands of years, the proportion of calories coming from beverages was relatively minor until about fifty years ago when soft drinks started to proliferate.
Thirst is an important drive that needs to be satisfied, and sometimes water just doesn’t satisfy. The trick is to make sure you’re not going extreme in calorie-laden drinks, as they can crowd other nutrients out of your diet. They also may not give you the satiety signals you need to help you stop. (The temporary feeling of fullness from the volume of liquid in your digestive tract doesn’t last long.) But remember, dietary variety is good. You don’t want to cheat yourself out of some of the nutrients that can come from drinks, like the anti-oxidants found in grape juice and wine, especially if these drinks are more appealing to you at times than the real deal grape. Most important is to learn to pay attention to what you are consuming and how it truly feels in your body. Doesn’t matter if it’s juice, a soft drink, or a “sports energy drink,” if you over-indulge, chances are it will show up unfavorably in your energy level and mood. Is this true for you? Remember the good old days when drinks were served in 8 ounce portions—not the gallon containers we now find in movie theaters?