There are many theories out there as to why obesity rates have been increasing in the West over the last forty years.
One of the most convincing and well-researched was put forward by two scientists – David Raubenheimer and Stephen Simpson – in the early 2000s. Their idea probably explains why obesity levels have been rising in recent decades and the simple change that people can make people in their diets to lose weight.
This theory is known as the “protein leverage hypothesis” and today we’re going to unpack it and explain how to use it in your life.
What cannibalistic grasshoppers can teach us about the innate hunger for protein
You’ve probably read about plague-level swarms of locusts and crickets. From time to time like an apocalypse, they march across the landscape, devouring everything in their path.
Here’s something you might not know: When crickets hit a patch of land that doesn’t have nice, tasty starches, they will start eating the other crickets.
Why would a herbivorous insect become cannibalistic?
Dr. Raubenheimer, who is an entomologist (scientist who studies insects), decided to investigate this question. He discovered that crickets and grasshoppers consume wheat, corn and cotton because they are looking for a specific macronutrient.
No, not carbs.
Protein.
Crickets eat all this starchy food because their bodies are hungry for the protein it contains. When there is plenty of grass and grain to eat, crickets will simply eat it because these food sources have the right mix of carbohydrates, fats and, most importantly, protein they need to thrive.
When they hit a piece of land with plant life that doesn’t contain a lot of protein (like you might find in a desert), the crickets will start eating each other. Grasshoppers have an innate hunger for protein that won’t stop.
Raubenheimer and Simpson decided to take a closer look at crickets’ innate desire for protein in the lab.
They found that if you place two bowls in front of crickets, one filled with food containing a natural balance of carbohydrates, fats and protein and the other filled with food modified to lack protein, the crickets will ignore the lack of protein. food and only eat foods that provide them with adequate protein.
Raubenheimer and Simpson then investigated what would happen if they gave crickets access only to foods that had been modified to have varying proportions of carbohydrates, fat, and protein.
What they found is that regardless of the food they were assigned, the crickets seemed to have a target amount of protein – 210 mg per day – that they were trying to achieve with their diet and would eat until they reached that target. If the food they were given had a higher percentage of carbohydrates but less protein, they would eat more total calories on their way to meeting their protein goal. If they ate food with a higher percentage of protein, they would eat fewer total calories because they would reach their protein goal sooner.
Raubenheimer and Simpson observed this phenomenon in other animals such as rats, dogs and cats. Animals will eat feed until they reach a certain daily protein target. Once they achieve this goal, they stop eating.
If you manipulate the feed you give animals so that it is lower in protein but higher in fat and carbohydrates, they will eat more total calories.
If you make the food higher in protein and lower in carbohydrates and fat, they will eat fewer total calories.
Here’s a concrete, hypothetical example to illustrate this idea: Suppose you give animals pellets of food that each contain 100 calories, but in varying proportions of carbohydrates, fat, and protein. In one pellet type, 70% of calories come from carbohydrates (17.5 grams), 20% from fat (~2 grams), and 10% from protein (2.5 grams). In the other pellet, 70% of the calories come from protein (17.5 grams), 20% from carbohydrates (5 grams), and 10% from fat (~1 gram).
If an animal needs 100 grams of protein per day and is given the first type of pellet, it will eat 40 pellets, or 4000 calories per day. If he is given the second type of pellet, he will eat 6 pellets, or 600 calories per day. The animal receiving the lower protein feed will eat nearly 7 times as much feed to reach its daily protein target.
The idea that protein consumption drives total calorie consumption is a now-proven phenomenon called “protein leverage.” Protein has leverage on the total feed intake of animals. If you move the protein lever up or down, it will increase or decrease the amount of other macronutrients a body will consume.
Raubenheimer and Simpson posited that, like other animals, humans are also affected by protein leverage—that we have an innate, specific hunger for protein, and that our bodies have a target amount of protein that they try to consume each day. maintaining health. And lo and behold, we do!
If you manipulate people’s diets to be higher in protein and lower in carbohydrates and fat, they will eat fewer total calories because they will reach their protein goal for the day faster. If you feed people a diet higher in fat and carbohydrates and lower in protein, they will eat more total calories on the way to reaching their protein goal.
The protein goal will vary from person to person, depending on age, gender, activity level and weight. But for most people, it’s about 0.36 grams of protein per kilogram of body weight per day.
These observations led Raubenheimer and Simpson to formulate the “protein leverage hypothesis,” which says “that the dominant appetite for protein combined with a reduction in the ratio of protein to fat and carbohydrates in the diet leads to excessive energy intake and therefore could promote the development of obesity.”
Living in a protein-diluted food environment makes us fat
While absolute protein intake has remained stable over the past fifty years, fat and carbohydrate consumption has increased dramatically.
Why do we eat more carbohydrates and fat?
The protein leverage hypothesis has one possible answer. When energy-dense carbohydrates and fats dilute the proportion of protein in our diet, we will consume more food to compensate for insufficient protein intake. We need to eat more overall to reach our protein goal.
For example, to get 20 grams of protein at breakfast, you could eat three eggs, for a total of 225 calories. Or, you could eat two bowls of cereal and milk at 450 calories.
In modern times, we live in a dietary environment in which we are surrounded by highly processed foods that are high in carbohydrates and fat but low in protein. To meet our protein goal in this low-protein diet environment, we need to eat a lot of extra calories in carbohydrates and fat. All those extra calories add up and make people fat.
How to use the protein leverage hypothesis to fight the bulge
We can use the protein leverage hypothesis to our advantage to lose weight.
As shared on the podcast by protein researcher Dr. Donald Layman, increasing protein intake is probably “the most effective way to correct body composition and lose weight.”
Studies show that people on higher protein diets eat fewer calories. This is partly because protein helps you feel satiated and full. And protein has this effect not only because it doesn’t raise your blood sugar as much as carbohydrates, but also because of the dynamic leverage of protein.
When you eat foods higher in protein, you don’t need to eat as much food to meet your protein goal. You don’t feel as hungry and have less of a problem with overeating. By hitting your protein goal earlier, you can stop eating earlier.
So if you want to lose weight in the low protein diet environment that characterizes the modern world, you have to they give priority protein in your diet.
When deciding what to eat, make sure protein is an important part of your meal or snack. Dr. Layman says that “the first thing you eat at any meal should be the protein part. Your first bite should be a protein bite. So when they bring out the bread or chips or while you’re waiting, you can’t eat it until the protein arrives.”
Beware of what Raubenheimer and Simpson call “protein baits.” When you’re low in protein, your body craves salty foods, which are usually high in protein, to motivate you to meet your protein goal. But many processed foods these days, like barbecue chips, offer salty flavor but contain little real protein. If you satisfy your cravings with a salty, low-protein food, you’ll continue to be hungry as your frustrated body continues to strive to reach its protein target, and you’ll overeat and consume too many calories. When your body is hungry for something salty, satisfy that craving with a food that’s actually high in protein, not a fatty carb bomb masquerading as protein.
All of this doesn’t mean you have to go on an extremely high protein diet. You don’t have to go on the carnivore diet and eat nothing but meat and salt. You just need to aim to get at least 0.36 grams of protein per kilogram of body weight per day. If you go higher, you may get better results in both weight loss and muscle building. I would recommend getting up to 0.8 grams of protein per pound of body weight. As a dedicated weightlifter, I try to eat one gram of protein per pound every day.
Prioritizing protein along with high-fiber whole foods like oatmeal and vegetables will keep you feeling fuller longer and result in you eating fewer calories without having to exert a lot of willpower. You will be better able to eat in moderation, instead of cleaning your plate like an insatiable grasshopper.
Sources/Related Resources
For more information on the role protein plays in weight and health, listen to our podcast with Dr. Don Layman:
