One of the most amazing effects of the Keto diet or any significant reduction of carb intake is how it significantly changes the appetite.
- Hunger is reduced
- Out of control cravings for sugar, sweets and other carbs are gone
- Many report they no longer wake up in the middle of the night to sleep eat, a common occurrence among those whose appetite is wrecked by carbs
- Calorie counting becomes obsolete as the appetite is reduced naturally and low carb eaters simply want and need less food, without starvation or will power.
This is the reason why Keto does not include calorie counting, but instead advises people to eat to satisfaction, which amazingly comes from much less food than when carb intake is substantial.
Why is this so? There are two main reasons.
The Leptin Equation
The hunger-regulating hormone leptin works in the brain to send signals to the body that you are full, so it registers the need to decrease food consumption, increase metabolic rate and shut off the hunger response.
This is a complicated process, and an ongoing cycle that repeats itself, as you get hungry again and again throughout the day.
Therefore, as the levels of leptin rise and wane, so does the sense of hunger (up or down) and to some extent your metabolic rate.
Between meals, your fat mass decreases in size as it is being used for energy, and so does the level of leptin.
Less leptin crosses the blood brain barrier, less binds to its receptors and the brain sends the signal to let you know it’s time to eat again.
The critical point is when leptin crosses the BBB, because if it cannot make it across, the hunger response is never shut off, no matter how much leptin there maybe in the blood stream.
This problem, and the often the plight of the obese is when leptin never reaches their brain to shut-off the hunger response, and hunger results in eating, which more makes more fat stores, which makes more leptin, which cannot shut off the hunger response because it cannot get to the brain, in a never ending cycle.
Why does this happen?
Researchers from St. Louis and Japan (Banks A, Coon AB, Robinson SM, Moinuddin A, Shultz JM, Nakaoke R, Morley JE, et all, Triglycerides induce leptin resistance at the blood-brain barrier) figured out that triglycerides, which are fats found in the blood stream interrupt the passage of leptin across the blood brain barrier.
When triglyceride levels are high, as they are in most overweight and obese people, they block this passage of leptin where it can signal that the body has had enough food and is satisfied.
What does this have to do with a low carb diet?
It is a well-known fact that a low-carb diet results in a dramatic reduction in triglyceride levels.
This reduction ensures that leptin can get to the brain to successfully reduce hunger.
The reduction in triglycerides happens pretty fast once carb intake is reduced, and is one of the main reasons that low carb eaters have a substantial reduction in hunger.
As an added benefit, once leptin gets to the brain it boosts thermogenesis (fat burning) and so the metabolic rate increases.
This is also one of the main reasons that low-carb wins the battle over low fat diet plans.
A low carb diet can result in a naturally lower caloric intake as people are simply not as hungry as they are when eating many carbs.
They are not white knuckling it through caloric restrictions as they do on the many high carb/low fat plans where people need much more support to get through the dietary day.
Conversely, low fat diets raise triglycerides levels and eventually most who follow these types of plans will give into that hunger.
Blood Insulin Levels
Another way that limiting carbs regulates appetite is by regulating insulin.
Researchers at Temple University School of Medicine found that lowering carb intake alters blood insulin levels in ways to promote appetite suppression and satiety.
10 obese people with type 2 diabetes were placed in the hospital 14 days, and each bite of food they took was analyzed and daily blood samples were taken.
For 7 days they ate a normal diet, then for 14 days, their carb intake was limited to 21 grams per day, and they were allowed to east as much protein and fat as they wanted.
- In the end, analysis showed they ate 1/3 fewer calories on the low carb days, than they ate on the 14 days of a regular diet that included carbs
- They lost an average of 3.5 pounds during the low carb days
- Their blood insulin levels dropped by 23%, which resulted in the suppression of appetite
Carbohydrates stimulate the appetite and also cause out of control cravings, in part due to the erratic blood sugar swings and insulin hikes they cause, but a low carb diet actually works as natural appetite suppressant.
This is one of the main reasons that keto and other low carb plans work very well for those who have struggled all their lives white knuckling it through the various low calorie and low fat diets they have endured.
In many cases, there is no willpower, hunger is not an issue, and a new lifestyle takes over naturally.