Chinese food is one of America’s favorite meals.
In the New York City metropolitan area there are more than 1783 Chinese
restaurants. That’s one restaurant for every 250 Chinese people in the city.
Eating Chinese food can be spicy or bland, rice or
noodles, but it's always filling. The problem is that you supposedly feel hungry
soon after eating. Could it be a devilishly sly plan to get you to order more wontons?
The truth is that some people do feel hungry soon after a Chinese
meal, enough people to keep the old saying in our lexicon.
The first published instance of the Chinese food dilemma
was in a 1934 article in the Golden Book. Nowadays the problem is called Chinese
Food Hunger, or CFH for short. Can we pinpoint why people get hungry after a plate of Chinese food
before the next mealtime?
Getting hungry in scientific terms is an issue of satiety. A hunger problem is really a
satiety problem; less satiety = more hunger. This idea led to the creation of a satiety index by Holt et al., in 1995, ie. just how full certain foods make you feel. The
index uses the same number of calories of different foods and converts the
self-reported feelings of fullness over time by the participants to a number
scale.
Chinese food from different parts of China uses either rice
or noodles as a starch. These carbohydrates have satiety indices of 130
and 119, respectively. Potatoes, on the other hand, have a satiety index of 323,
the highest of any food tested. This leads to one hypothesis of CFH - Americans
think Chinese food makes them hungry sooner because they're comparing it to
potato based meals.
People have been eating fewer
potatoes in the last 30-40 years, McDonald’s French fries not withstanding. This may account for why many people think we talk about CFH less than we used to. However,
a 2013 study
showed that despite the high satiety of potatoes, they didn't
significantly reduce the amount of food that was consumed later as compared to
other meals. So maybe it means nothing.
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You can see
that hunger and fullness feelings are well
controlled
and complex. Basically, the more green input,
the fuller
you will feel and the less you will seek out food.
This is just
one of the ways our brain tricks us into wanting
the things
that we need.
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The regulation of satiety and
hunger is controlled by many hormones. Several gastrointestinal hormones act in
satiety.
Cholecystokinin (CCK), pancreatic polypeptide,
peptide YY, glucagon-like peptide-1, oxyntomodulin – these all work to
increase
satiety and
decrease food intake. Ghrelin, on the other, is produced by select
cells of the stomach and pancreas and acts to decrease satiety and increase
food intake. These signals are monitored and regulated in the hypothalamus and
arcuate nucleus of the brain – the so-called hunger centers.
Leptin works in the opposite direction as ghrelin. Leptin
hormone is produced by fat cells (adipocytes). It stimulates hunger when fat cells
are being used as energy source, as when caloric intake is low. Leptin
increases satiety when caloric intake is high - more leptin is put out by fat
cells. Leptin also acts in reward centers; more leptin (more fat = a more fed
situation) decreases the reward felt by eating food, and reduces the craving
for reward of food. These are complex pathways.
So what is it in Chinese food that affects the levels of
satiety hormones?
Monosodium glutamate (MSG) is a common whipping boy. People
have said MSG is unhealthy, raises blood pressure, and is toxic. Some people really do
have a bad reaction to MSG, referred to as Chinese Restaurant Syndrome (don’t
confuse CFH and CRS). In CRS,
suffers show reddened skin, headache, chest pain, sweating, and numbness. But most
people don’t have a problem with MSG and survive Chinese food just fine.
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MSG can lead
to facial flushing like on the left. However, the
reduction in
MSG use has not eliminated the problem for
some people.
In many foods, the MSG has been replaced with
another
flavor enhancer called E635. This is a combination of
two
ribonucleotides (IMP and GMP) with two sodium molecules
on each.
E635 can lead to similar or worse problems as MSG in
susceptible
people. The smile on the right is after she discovered
how to avoid
her problem foods.
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Still, the vast majority of Chinese restaurants
have cut back on MSG. This is another reason why some people say that
complaints about Chinese food making them hungry sooner have decreased –
because MSG is the culprit and less MSG is being.
Not a very scientific determination.
A study in 2011 showed that MSG does not alter ghrelin,
GLP-1 or insulin levels, and actually brings more distention of one end of the
stomach, so it probably makes you feel more full rather than less full.
Don't worry, there are several other possible culprits. For one thing, most
Chinese natives eat less meat as a part of the meal as compared to Westerners.
Do low protein meals lead to decreases in satiety hormones or increases in
hunger hormones? Probably not,
a 2014 study showed that satiety hormone
profiles were similar between good vegetarian diets and high meat diets.
How about low fat meals – less red meat
and processed foods could also result in low fat Chinese meals.
Does eating low fat mean you’ll be
hungrier sooner?
One problem with protein and/or fat hypotheses is that Chinese
food as served in American restaurants today is not very Chinese. They use more
meat, more fat, and more sauce than would be included in traditional Chinese
meals. So I don’t think we can use them to explain CFH.
The idea of glycemic
index is very hot right now. Originally developed to try and help diabetics
better manage their blood sugar levels, weight loss gurus now lament that high glycemic
index foods put the sugar into your blood very quickly and then cause you to
crash to lower blood sugar levels sooner. This leads to overeating and weight gain.
Eating low glycemic index foods (like vegetables and fruits) means that you
don’t digest food as fast, and stay full longer.
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Here are
examples of high and low glycemic index foods and
their
effects on blood sugar levels. Note that high GI foods don’t
crash your
blood glucose at two hours, it’s just a little lower.
Might this
be enough to increase appetite?
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Some recent studies indicate low GI meals result in
more CCK and didn’t increase ghrelin. This would suggest that Chinese foods
high in vegetables would maintain satiety longer rather than make you hungry sooner. However,
one 2008 study in
overweight women showed that high GI foods led to more satiety hormones and
less hunger. But again, American Chinese food uses lots of rice and sugary
sauces, so it is has a much higher GI than traditional Chinese food.
Final answer
– we don’t know why eating Chinese food results in being hungry again so soon.
Science can be frustrating. Maybe it really is just a phrase that snuck into
our language and gets repeated even though it’s not real. Sort of like the
misconception that we only use 10% of our brain.
I suggest a
rigorous, government-funded study. First to be determined is whether the
satiety index of a Chinese food meal is significantly lower than that of an
Italian, Mexican, or American meal. Step two would be to determine the effects
of every Chinese food on the satiety and hunger hormones. If no food alters
hormone levels markedly, then a study of pleasure center activation would be
necessary. Any way you cut it, we’re going to need a lot of chopsticks, fortune
cookies and small white cardboard boxes.
contributed by
Mark E. Lasbury MS, MSEd, PhD
As Many Exceptions As Rules
Neacsu M, Fyfe C, Horgan G, & Johnstone AM (2014). Appetite control and biomarkers of satiety with vegetarian (soy) and meat-based high-protein diets for weight loss in obese men: a randomized crossover trial. The American journal of clinical nutrition, 100 (2), 548-558 PMID: 24944057
Geliebter A, Lee MI, Abdillahi M, & Jones J (2013). Satiety following intake of potatoes and other carbohydrate test meals. Annals of nutrition & metabolism, 62 (1), 37-43 PMID: 23221259
Boutry C, Matsumoto H, Airinei G, Benamouzig R, Tomé D, Blachier F, & Bos C (2011). Monosodium glutamate raises antral distension and plasma amino acid after a standard meal in humans. American journal of physiology. Gastrointestinal and liver physiology, 300 (1) PMID: 21030612
