Thylakoids come from green leaves, not from outer space or
from the lab of a mad scientist. Thylakoids are making headlines as a natural
appetite suppressant, but before you buy into the idea that they can help you
with your weight, wait – take a look at the fine print to Thylakoid Magic.
Green-Eyed Insight on
Appetite Suppressants:Thylakoids
Food Science in the News - Oct 23rd, 2013
The Findings
This is what you'll see in the headlines:
"Thylakoids
are natural appetite suppressants; they promote weight loss by controlling
hunger hormones"
"Eat greens and Lose Weight"
The Research
Notice how scientific studies have very descriptive titles. That's pretty typical in the science-world because scientists know some people
will only read the title of the paper it took them 3+ years to write and
publish:
Supplementation by thylakoids to a high carbohydrate meal
decreases feelings of hunger, elevates CCK levels and prevents postprandial
hypoglycaemia in overweight women
The Details
Overweight women (not lean, healthy people with their
appetites in check and no weight to lose) were given a high-carb breakfast. The
women who had thylakoid powder mixed into their blackcurrant jam (henceforth
"special jam") had decreased feelings of hunger and elevated CCK
levels. CCK is the "satiety hormone" so an increase in CCK helps you
feel fuller, longer.
This study was single-blind, meaning the scientist knew which
women got the "special jam". This study was also randomized, meaning every patient got the chance to eat the "special
jam" one morning and the normal jam the other morning, but not every women
got the special jam first. This is important because it eliminates "First
Position Bias". In other words, after you've been through Day One of the
study, you know what to expect on Day Two. That might affect your answers on
a "How Hungry Are You" survey or change your actions the night before you're
supposed to report for the study.
The Bad Assumptions
The following statements are common in studies like these,
but closer inspection shows they are more flash than substance, leading to
confused consumers and frustrated food scientists:
ONE - The group that got
more food reported less hunger than the group that got less food.
It seems rather obvious but I've read papers that forget to
control calories in this type of study.
For example, there's the study wherein half the group got a
sugary energy drink, the other half got water. The group that got the sugar
performed better. Well no duh, the other group was starving because all your participants had to fast the night before (not uncommon but hello,
something to keep in mind when you're testing the effects of an energy drink).
Fortunately, this study on thylakoids did control for such things. The
calories between the "special jam" and the normal jam ranged from
537-554 calories and the carb/fat/protein breakdowns for the whole meal were
the same (71% carbs with 11g sugar, 16.9-17.9 grams fat, 28.4-29.6 grams
protein).
TWO - When people eat before they eat food, they eat less food when they eat.
In this particular study, the thylakoids didn't have any affect on how much the women consumed at that particular meal. In fact, even though the "special jam" did boost CCK (satiety hormone levels) more than the normal jam, there wasn't a big difference between the two until 180 minutes after the meal. The bad news is thylakoids won't prevent you from overeating unless you eat food (such as a green leafy salad) before you eat food (meaning your meal). The good news is A) this study was done in women, not just in lab rats, and B) the thylakoids COULD help the women consume less food at the next meal. That brings us to the next unfortunate assumption.
THREE - This small effect will change the course of your whole day.
There are some actions we
can do in the morning that significantly alter the course of the day: workout
before work, eat breakfast instead of skipping it, putting the cell in the
glove box to remove driving hazard temptation…and so on. When it comes to one
meal affecting the volume of food consumed at the next meal, I remain
skeptical.
BOTTOM LINE
There's no question eating leafy greens is good for you, so if you need to
believe that thylakoids can help you eat less throughout the day then, by all
means, add more leafy greens to your diet.
But if you really care about suppressing your
appetite and eating less food throughout the day, remember this: Aside from
Volumetrics and social cues, there are many factors that affect how much food
is consumed at a meal. One of my reasons for being skeptical about any
appetite suppressant is that "Unit Bias" and "Portion
Distortion" remove hunger from the equation. Unit Bias is best visualized
as one of those ginormous muffins or a tall can of Arizona Iced Tea. Just
because it's one container, doesn't mean it's one serving. Perhaps thylakoids can help control appetite, but this is only part of the picture. The other part is how to become more cognizant of those satiety cues instead of portion sizes.
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