Niman was
examining the health impacts of sugar at the same time as WHO. In
researching and writing her latest book, she dug into studies that found
evidence sugar does more than just lack nutrients. “The sugar is going
to actually damage your body. It’s not just that you’re not going to get
the nutrients,” she said.
The link between sugar and disease is not a new one. Decades ago, nutrition professor
John Yudkin wrote a book called
Pure, White, and Deadly in
which he posited that sugar was the culprit behind heart disease and
type 2 diabetes. The food industry fought back. This was the era of
lowfat, not low sugar. (In his book, Yudkin even quotes a sugar industry
advertisement claiming that sugar makes you thin. Go figure that out.)
The
general term “sugar” can mean any number of things. Table sugar, or
sucrose, is composed of a glucose molecule bonded to a fructose
molecule. Glucose is what plants make during photosynthesis and it’s
half as sweet as table sugar. Fructose, naturally found in honey and
many fruits, is 70 percent sweeter than table sugar.
On
your tongue, you taste a difference in sweetness between glucose and
fructose. Once in your body, the difference continues. Glucose is
metabolized by every cell in your body. After you eat, your blood
glucose levels rise, and your body releases
insulin. The insulin helps your muscles, fat and liver absorb the glucose, decreasing your blood sugar.
Levels of another hormone,
leptin, also rise. Leptin
regulates your appetite; once you’ve eaten and your body has plenty of fuel to keep going, leptin tells you to stop. Another hormone,
ghrelin, decreases. Ghrelin stimulates your appetite, and after you’ve eaten, it’s already done its job.
Fructose, on the other hand, is only metabolized by your liver. The title of
a 2004 study says
it all: “Dietary fructose reduces circulating insulin and leptin,
attenuates postprandial suppression of ghrelin, and increases
triglycerides in women.” In other words, after you eat fructose, your
body never gets the message, “You’ve eaten enough, now stop.” As for
those increased triglycerides, well… another word for triglyceride is
“fat.”
In
scientist-speak, “Compared with glucose, the hepatic metabolism of fructose favors lipogenesis, which may contribute to
hyperlipidemia and obesity.” Translated, that says when fructose is metabolized in your liver, it is often converted to fat.
These
facts about fructose are often cited in arguments against high-fructose
corn syrup, but remember that sucrose, honey and even apple juice
contain lots of fructose too.
One
consequence of overdoing it on sweets is called “
metabolic syndrome.”
That’s a medical term for a number of risk factors for heart disease,
diabetes and stroke: a large waistline, bad cholesterol, high blood
pressure, and high fasting blood sugar. In fact, fructose and sucrose
are such reliable causes of metabolic syndrome that scientific papers
often use the terms “
fructose-induced metabolic syndrome” or “
sucrose-induced metabolic syndrome.”
Some scientists add other evils to the list, including kidney disease and stroke. A
2010 study found
that “Fructose feeding has now been shown to alter gene expression
patterns… alter satiety factors in the brain, increase inflammation… and
induce leptin resistance.”
If that sounds so bad that you decide
to switch your sweetener to pure glucose (sold under the name corn
syrup, and not the high-fructose variety), keep in mind that an influx
of glucose into your body
spikes your blood sugar,
followed by a crash. This is especially true when the sugar comes in
liquid form. Your body also breaks down complex carbohydrates like whole
grains into glucose, but then the glucose is released more slowly into
your bloodstream. In 2013, scientists found that lower blood sugar may
even
improve memory.
All in all, one
report estimates
“30%-40% of healthcare expenditures in the USA go to help address
issues that are closely tied to the excess consumption of sugar.”
The
sad truth is that there’s no free lunch. Even when you eat “sugar-free”
cake sweetened with honey or fruit juice, it’s all sugar to your body.
(However, raw unprocessed honey provides some
health benefits,
whereas refined sugars do not.) For an experiment, go a day with only
six teaspoons of sugar (25g) if you’re a woman, or nine teaspoons (38g)
if you’re a man. Don’t forget to check foods you wouldn’t expect for
hidden sugars, like bread, salad dressing, pasta sauce, and ketchup.
Suddenly, the amount of sugar we eat in our normal diets becomes
staggering.
Longer term, if a complete sugar makeover sounds
unimaginable to you, start by cutting out sugary drinks, including fruit
juice. You might want to skip the
diet sodas too, since research shows they can be even worse than the “real thing.”
If
your heart is palpitating with dread at the very thought of giving up
sugar, you’ve arrived at one of the reasons why we eat so darn much of
it. Some say it’s addictive, and a 2007
study found it gives your brain a reward even greater than that of cocaine.
In his book
The End of Overeating: Taking Control of the Insatiable American Appetite,
former FDA commissioner David Kessler examined what drives wanting in
food. “Liking is pleasure but wanting is an urge to it,” he explains. “I
need it, I need it to make me feel better. We looked in animals to see
what was the most reinforcing. Was it the sweetness? Was it the fat? Was
it the flavor? We found that sweetness drives wanting more than
anything else. It drives—if you look at animals or people—how much
effort they’ll expend for it. How hard they will work for it.”
You’ve
heard the old adage, “A moment on your lips, a lifetime on your hips.”
The pleasure gained from food is so fleeting. If I eat a cookie now, I
will experience a few moments of pleasure, and then no more. I can
extend that pleasure briefly by eating a second cookie. And then it’s
gone. To keep feeling that pleasure, I would have to keep eating
cookies—at least until I feel sick from eating too many. Yet many of us
are more than willing to continue jamming cookies down our throats even
if we want to be healthy and we know that cookies are not health food,
for the ephemeral bliss they provide.
“We know that sweetness can
increase the pleasure centers of the brain, the opioid centers,” Kessler
continues. “We know it can serve as a mild pain relief… I’m eating
something that is sweet—it can change how I feel. So it’s salient. It is
powerful. It’s directly hard-wired from our sensory receptors in our
mouth to our brain. You don’t even have to go through the bloodstream.
It’s a very powerful molecule because it’s directly wired to our brain.
And it can drive want.”
He adds that, “Sweetness isn’t the only
driver of wanting. Add fat to that, it becomes more powerful. Add color,
add texture, add temperature, add mouthfeel. Kids’ candies are just
very simple, but as you get older you want more levels of stimulation.
But at the core of most foods that are hard to resist there is
sweetness. Now a lot of that has to do with past learning and past
memory. It’s not always sweetness, depending on your past learning—but
there’s no doubt that sweetness is driving.”
Kessler goes into
even greater detail in his book. He looks at the impact of priming, when
a single taste of a food triggers what he calls “conditioned
hypereating.” He points out how the food industry taunts us, “Bet you
can’t eat just one.” Sadly, that is probably true. Even if you’re not
particularly hungry, after a friend convinces you to have “just a taste”
of ice cream, you’re more likely to order an entire cone. Why do you
think Whole Foods is so generous at giving you free samples of its cakes
and gelato?
Kessler, and later Michael Moss (in his book
Salt Sugar Fat)
examine how the food industry capitalizes on our hardwired drive for
sugar (and salt and fat). Moss details food manufacturers’ efforts to
improve their products nutritionally without sacrificing flavor (or
sales) or increasing price. Sometimes, a healthier but higher priced
substitute, like an herb, could compensate for salt, sugar and fat. More
often, when the manufacturers reduce one of those three elements, they
compensate by boosting one or both of the other two.
In response
to her research, Nicolette Hahn Niman almost entirely gave up sugar. She
limits herself to a few squares of dark chocolate each day, and she
reports that she’s kicked her sugar habit, and the cravings that would
make her fall back to it.
Eschewing sugar is not impossible,
particularly after the initial cravings go away, but it can be difficult
in our society unless you cook all of your own food. Even then, it can
come off as socially gauche when you’re dining with friends or
co-workers and you’re the only one who isn’t gushing over the triple
chocolate mousse cake someone brought to the party.
That said, there are other flavors out there, including salty, bitter, spicy, sour, and
umami. Perhaps we Americans would do well to explore them.
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