Some Surprising Truths About Hunger And Satiety

This is Dr. Barbara Rolls. She’s Professor and Guthrie Chair in Nutritional Sciences, and Director of the Laboratory for the Study of Human Ingestive Behavior at Pennsylvania State University, after graduating herself from Oxford and Cambridge (yes, both). Her “awards and honors” take up four A4 pages, so we won’t list them all here.

Most importantly, she’s an expert on hunger, satiety, and eating behavior in general.

What does she want us to know?

First and foremost: you cannot starve yourself thin, unless you literally starve yourself to death.

What this is about: any weight lost due to malnutrition (“not eating enough” is malnutrition) will always go back on once food becomes available. So unless you die first (not a great health plan), merely restricting good will always result in “yo-yo dieting”.

So, to avoid putting the weight back on and feeling miserable every day along the way… You need to eat as much as you feel you need.

But, there’s a trick here (it’s about making you genuinely feel you need less)!

Your body is an instrument—so play it

Your body is the tool you use to accomplish pretty much anything you do. It is, in large part, at your command. Then there are other parts you can’t control directly.

Dr. Rolls advises taking advantage of the fact that much of your body is a mindless machine that will simply follow instructions given.

That includes instructions like “feel hungry” or “feel full”. But how to choose those?

Volume matters

An important part of our satiety signalling is based on a physical sensation of fullness. This, by the way, is why bariatric surgery (making a stomach a small fraction of the size it was before) works. It’s not that people can’t eat more (the stomach is stretchy and can also be filled repeatedly), it’s that they don’t want to eat more because the pressure sensors around the stomach feel full, and signal the hormone leptin to tell the brain we’re full now.

Now consider:

• On the one hand, 20 grapes, fresh and bursting with flavor
• On the other hand, 20 raisins (so, dried grapes), containing the same calories

Which do you think will get the leptin flowing sooner? Of course, the fresh grapes, because of the volume.

So if you’ve ever seen those photos that show two foods side by side with the same number of calories but one is much larger (say, a small slice of pizza or a big salad), it’s not quite the cheap trick that it might have appeared.

Or rather… It is a cheap trick; it’s just a cheap trick that works because your stomach is quite a simple organ.

So, Dr. Rolls’ advice: generally speaking, go for voluminous food. Fruit is great from this, because there’s so much water. Air-popped popcorn also works great. Vegetables, too.

Water matters, but differently than you might think

A well-known trick is to drink water before and with a meal. That’s good, it’s good to be hydrated. However, it can be better. Dr. Rolls did an experiment:

The design:

❝Subjects received 1 of 3 isoenergetic (1128 kJ) preloads 17 min before lunch on 3 d and no preload on 1 d.

The preloads consisted of 1) chicken rice casserole, 2) chicken rice casserole served with a glass of water (356 g), and 3) chicken rice soup.

The soup contained the same ingredients (type and amount) as the casserole that was served with water.❞

The results:

❝Decreasing the energy density of and increasing the volume of the preload by adding water to it significantly increased fullness and reduced hunger and subsequent energy intake at lunch.

The equivalent amount of water served as a beverage with a food did not affect satiety.❞

The conclusion:

❝Consuming foods with a high water content more effectively reduced subsequent energy intake than did drinking water with food.❞

You can read the study in full (it’s a worthwhile read!) here:

Water incorporated into a food but not served with a food decreases energy intake in lean women

Protein matters

With all those fruits and vegetables and water, you may be wondering Dr. Rolls’ stance on proteins. It’s simple: protein is an appetite suppressant.

However, it takes about 20 minutes to signal the brain about that, so having some protein in a starter (if like this writer, you’re the cook of the household, a great option is to enjoy a small portion of nuts while cooking!) gets that clock ticking, to signal satiety sooner.

It may also help in other ways:

Clinical Evidence and Mechanisms of High-Protein Diet-Induced Weight Loss

As for other foods that can suppress appetite, by the way, you might like;

25 Foods That Act As Natural Appetite Suppressants

Variety matters, and in ways other than you might think

A wide variety of foods (especially: a wide variety of plants) in one’s diet is well recognized as a key to a good balanced diet.

However…

A wide variety of dishes at the table, meanwhile, promotes greater consumption of food.

Dr. Rolls did a study on this too, a while ago now (you’ll see how old it is) but the science seems robust:

Variety in a Meal Enhances Food Intake in Man

Notwithstanding the title, it wasnot about a man (that was just how scientists wrote in ye ancient times of 1981). The test subjects were, in order: rats, cats, a mixed group of men and women, the same group again, and then a different group of all women.

So, Dr. Rolls’ advice is: it’s better to have one 20-ingredient dish, than 10 dishes with 20 ingredients between them.

Sorry! We love tapas and buffets too, but that’s the science!

So, “one-pot” meals are king in this regard; even if you serve it with one side (reasonable), that’s still only two dishes, which is pretty good going.

Note that the most delicious many-ingredient stir-fries and similar dishes from around the world also fall into this category!

Want to know more?

If you have the time (it’s an hour), you can enjoy a class of hers for free:

!

Want to watch it, but not right now? Bookmark it for later

Enjoy!