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“My job is ruining my diet! When I’m at work it seems I’m hungry all the
time. I notice I crave sugar and fats more as well. When I give in to these cravings they
only intensify. It seems the more I eat of these foods, the hungrier I become. I know I
should feel full, but I don’t. What causes this?”
Sometimes it’s difficult to discern the difference between hunger, appetite, and
cravings. They result from a complex interplay of internal and external factors. If
you’re unaware of the presence of these factors, you can throw your body’s
natural hunger cycle off, thereby sabotaging your weight maintenance goals. By understanding
what these factors are and how to identify them, you can get your healthy eating goals
back on track! Let’s begin with some simple definitions.
Hunger is a physical sensation in the stomach, signaling a lack of food. The gnawing or
dull pain may be accompanied by a strong desire to eat or even weakness. A natural eating
cycle begins with hunger. Eating patterns that disrupt the natural cycle include bingeing,
stringent dieting, fasting, purging through vomiting, laxatives, diuretics, or excessive
exercise, eating once a day, or “grazing” throughout the day.
Appetite is a desire that causes us to seek food for the purpose of tasting and enjoying
it. Appetite can be influenced by any number of things, including mood, stress, or external
and internal cues.
A craving is a strong urge to eat a specific food.
“So the food cravings I experience at work could likely be brought on by moderate
stress. That makes sense. Then what causes me to crave the types of food I do?”
While hunger is usually brought on by changes in blood glucose, fats, and insulin,
appetite and cravings are tied to the actions of certain brain chemicals—dopamine,
serotonin, and beta-endorphin. Foods interact with these chemicals to influence appetite,
satiety, and food preferences. Here’s how these brain chemicals work.
Dopamine is the brain’s pleasure chemical. Its effects include alertness,
energy, and quick response time. The brain makes dopamine from protein foods, such as
chicken, turkey, fish, or beef.
Serotonin acts as an antidepressant. Its effects include relaxation, reduced stress
and anxiety, slower response time, and satiety, especially for carbohydrates. While the
brain manufactures serotonin after a high-carb meal, only protein in the diet provides
serotonin’s chemical forerunner.
Beta-endorphin is the feel-good chemical said to induce runner’s high. It
reduces pain and distress, increases appetite, and promotes a preference for sugars
and/or fats. It also creates pleasure because it stimulates a dopamine response.
Beta-endorphin is triggered primarily by fats, sugars, and spicy foods.
“Sometimes I feel overwhelmed by food cravings. What factors trigger these
cravings?”
Appetite can be stimulated by external cues, including the sight or smell of appetizing
food or even the location of a favorite food, like the local bakeshop. An internal
cue—tasting a small amount of a certain food—can trigger the desire for
more. This “priming” involves dopamine. Priming can be quite strong when we eat
sugars and fats, so it isn’t always the best strategy to eat a food that you crave.
While the craving may be satisfied temporarily, the next step could be stronger craving,
or even a binge.
Negative moods, such as boredom, anxiety or depression, result from low levels of
one or more of the above brain chemicals and cause cravings, especially for starchy or sweet
carbohydrates. Studies suggest that carb-cravers may actually be using carbs in an attempt
to improve their moods.
Stress is another appetite trigger. While acute stress inhibits appetite, chronic stress
stimulates it. Over time, stress reduces serotonin and other chemicals, leading to
depression and cravings for carbs and sugars.
Diet can strongly influence mood and food cravings. Low-protein diets or regular
alcohol use diminish serotonin and dopamine levels. Deficiencies of B-vitamins—thiamin,
B6, and folate—can lower serotonin and dopamine levels, as well, leading to negative
moods, increased appetite, and cravings. Thiamin is found in whole grains, B6 in protein
foods, and folate in leafy vegetables. Eat these foods in abundance.
“How does dieting influence cravings?”
Low-fat diets can reduce levels of cholecystokinin (CCK), a chemical that is released when
fats and protein enter the small intestine. CCK is a powerful satiety agent that causes us
to reduce our carb intake. Lower levels of CCK that accompany low-fat diets lead to
increased carb intake.
Reducing dietary fats increases sugar intake; the reverse is also true. This phenomenon
is known as the “sugar/fat seesaw.” With the popularity of low-fat diets over
the past 15 years, the U.S. has seen a substantial increase in sugar consumption. USDA
figures from 1997 place U.S. sugar consumption at 150 pounds per year, 25 pounds higher
than in 1984, around the time of the initial popularization of low-fat diets. Consumption
of artificial sweeteners is also rising, and they trigger beta-endorphin, as well. The
beta-endorphin effects of sugars and sweeteners increase appetite and sugar cravings.
They also keep us eating longer.
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