How to Control Your Appetite with Red Light

Did you know that you are not supposed to be hungry all the time? Alternatively, that eating is supposed to make you feel uncomfortable so that you stop eating? People who do red light therapy for 2 hours every morning probably know this. I did not know that for decades! I changed my diet, and added red light to get control of my appetite.

Hunger is a biological imperative that says “YOU MUST EAT!” Fullness is another biological imperative that says, “YOU MUST NOT EAT!” The hormones ghrelin and leptin drives these feelings. When ghrelin is high, you are hungrier, and you eat more. When leptin is low, you are not satisfied with food, and you eat more. Red light therapy can decrease ghrelin so you feel less hunger. Red light therapy can increase leptin, so you feel full when eating. By decreasing hunger and increasing fullness, red light therapy helps you eat less and lose weight.

Red Light Therapy Decreases Ghrelin, Removing Feelings of Hunger

I have a friend who does not understand what it is like to crave food.

I asked her, “You don’t ever feel like food helps relieve stress?”

She put her hand on her tummy and said, “I just don’t feel like eating.”

Until recently, I always felt like eating. My grehlin was high, and my leptin was low.
Until recently, I always felt like eating. My grehlin was high, and my leptin was low.

Ghrelin Increases Hunger

Hangry: hungry and angry. If you get angry when you're ghrelin is too high, you might get hangry.
Hangry: hungry and angry. If you get angry when you’re ghrelin is too high, you might get hangry.

Maybe her ghrelin is low. She just doesn’t feel hungry.

The rest of us know what it is like to reach for another plate of Chinese food because we just don’t feel full.

It just tastes good, and it makes the mouth happy.

Overactive ghrelin production tells the brain “I’m still hungry!”

Ghrelin is supposed to recede after we begin eating.

When it does not recede, we can eat too much and still want more.

With too much ghrelin, hunger does not go away even when we overeat.

Red Light Therapy Reduces Ghrelin

Red light therapy reduces the the hunger hormone ghrelin
Red light therapy reduces the the hunger hormone ghrelin

Red light therapy decreases ghrelin production.

That means that red light therapy reduces those calls of “It is time to eat!”

In the study we will look at below, two hours of red light therapy every morning significantly decreased the amount of hunger hormone in the blood.

Sleep Deprivation/Light Therapy Groups
Hours of Sleep Each Night
2 Hour Light of This Type in Morning
8 hours
None
5 hours
None
5 hours
Red Light
5 hours
Green Light
5 hours
Blue Light

When red light shuts down the ghrelin production, it turns off the “please eat now” messages.

I reduced my ghrelin with red light therapy and cutting out carbs from my diet.

Red Light Therapy Increases Leptin, Driving Feelings of Fullness

My friend who doesn’t crave food might also have too much leptin.

When she puts her hand on her tummy to say “I just don’t feel like eating,” she is indicating that she feels uncomfortable at the idea of eating food.

Healthy people get a shot of leptin while they eat.

This is the message that says, “We’re full, stop eating now. If you keep eating, your stomach will hurt.”

Healthy people experience a biological imperative that screams “STOP EATING!” sometime during a meal.

Many of us are unfamiliar with this feeling.

Louis C.K. says that he doesn’t stop eating when he feels full.

He stops eating when he hates himself.

When leptin is high, you don't feel like eating because you feel full.
When leptin is high, you don’t feel like eating because you feel full.

Leptin Increases Fullness

My own experience after 50 years of eating carbs is that a low-fat diet turns off the leptin hormone.

A combination of two things helped me get that signal back:

  • long sessions of red light therapy
  • removing simple carbs from my diet

I had not felt full in decades.

My leptin was not telling me: “Please put down the fork.”

I got rid of simple carbs. I started eating veggies, protein, and fat. I soaked up red light every day. I was delighted to find out that I do, indeed, have a fullness alarm.

When we don’t have leptin, even a third serving of Chinese food does not make us feel “full.”

Leptin is the hormone that makes the tummy feel stretched, satisfied, and full.

If you feel these sensations, you are feeling leptin doing its job.

Nutritionists call this feeling “satiety,” which is “satisfaction with food.”

Red Light Therapy Increases Leptin

Red light therapy increases leptin production.

It ramps up the imperative “STOP EATING!” that is supposed to happen while you eat.

When you are satisfied with food, you do not feel compelled to eat more of it.

When you do not feel compelled to eat, you eat less!

Feeling full makes me actively dislike eating, so it is easier to eat less.

Red Light Controls the Appetite Better than Sleep

Sleep deprivation creates hormone imbalances
Sleep deprivation creates hormone imbalances

One study found that red light therapy can wipe out sleep-deprivation hunger problems.

Have you ever been sleep-deprived and felt unusually hungry?

Alternatively, you don’t get enough sleep, and one serving of dinner just does not seem to be enough food?

That is not a coincidence.

Our bodies confuse the need for sleep with the need for food.

When we need sleep:

  • ghrelin goes up, making us hungrier
  • leptin goes down, making us unaware we are full of food

In the study, they gave one group a regular night’s sleep, and no light therapy.

This group had the baseline ghrelin (“I’m hungry”) and leptin (“I’m full”) hormone levels.

Then they restricted sleep to 5-hours.

These subjects got hungrier (they had more ghrelin).

They also did not get full (they had less leptin).

Then they gave the sleep-deprived subjects two hours of light therapy upon wakening.

The subjects got red, blue, or green light therapy.

The red light group had less ghrelin and more leptin than the group that had a good night’s sleep.

A subject with 5-hours sleep did better with red light than a subject with 8 hours of sleep but no red light.

You can control your appetite with red light even if you are sleep-deprived.

Controls Had No Light Therapy

Controls had 8 hours of sleep and then dim light, or 5 hours of sleep, and then dim light.
Controls had 8 hours of sleep and then dim light, or 5 hours of sleep, and then dim light.

The study had two control groups.

The first group had 8 hours of sleep, which should be enough to reset and repair the body overnight.

The second group had 5-hours of sleep, which we would consider sleep-deprived.

These two groups experienced a dim light each morning.

Subjects Had Red, Green, or Blue Light Therapy

Controls had 5 hours of sleep. Then they had 2 hours of either red light, blue light, or green light therapy.
Controls had 5 hours of sleep. Then they had 2 hours of red light, blue light, or green light therapy.

The test subjects were all sleep-deprived. They did not nap. Researchers monitored their sleep with body activity trackers.

The sleep-deprived had 2 hours of light therapy upon waking.

They got red light, blue light, or green light.

Light vs. Sleep: Who Wins?

Light Therapy vs. Sleep: Who Wins?
Light Therapy vs. Sleep: Who Wins?

The study compared five groups as follows:

  • 8 hours sleep, no therapy
  • 5-hours sleep, no therapy
  • 5-hours sleep, red light therapy
  • 5-hours sleep, blue light therapy
  • 5-hours sleep, green light therapy

We know that sleep deprivation increases ghrelin and decreases leptin.

Which group do you think had the lowest hunger hormone levels?

Which group do you think had the highest fullness feeling hormones?

If lack of sleep causes ghrelin to go up, the sleep deprived 5-hour groups should have the highest ghrelin.

If lack of sleep causes leptin to go down, the sleep deprived 5-hour groups should have the lowest leptin.

That is not what happened.

Red Light Beat Sleep’s Effect on Hunger

Sleep deprivation plus 2 hours of red light was better than a full night's sleep
Sleep deprivation plus 2 hours of red light was better than a full night’s sleep

The group with 5-hours of sleep and 2 hours of red light therapy did the best at both suppressing ghrelin and increasing leptin.

The 5-hour sleep + red light therapy had:

  • the lowest ghrelin hormone (the least hunger)
  • the highest leptin hormone (the most feeling of fullness)

The sleep-deprived red light group did better than:

  • the full night sleep group
  • the 5-hour sleep group
  • the 5-hour sleep and green light group
  • the 5-hour sleep and blue light group

If red light can help appetite this much while sleep deprived, imagine what it can do if you have a good night’s sleep.

The Red Light Weight Loss Formula

Red light is the appetite control formula
Red light is the appetite control formula

If you wanted to be literal, you could follow the formula in this article.

  • Deprive yourself of 3 hours sleep.
  • Do 2 hours of RLT in the morning upon waking.

That is silly, because depriving yourself of sleep is still a bad idea.

The bottom line of this study is that 2 hours of red light therapy suppresses hunger and increases feelings of fullness.

Get enough sleep, and do your red light therapy.

All Light Therapies Overcame Sleep Loss

Sleep is still vital to health. Red light can overcome some of sleep deprivation's effects on appetite.
Sleep is still vital to health. Red light can overcome some of sleep deprivation’s effects on appetite.

In the study we are looking at in this article, the red light group was short on sleep.

Sleep deprivation is going to increase ghrelin and decrease leptin.

Despite that hormone handicap, that red light group still had lower ghrelin and higher leptin than the well-rested group.

I wonder what would have happened if one of the groups had enough sleep and 2 hours of red light therapy.

Unfortunately, researchers did not test that combination in this study.

It only makes sense to hypothesize that a good night’s sleep plus 2 hours of red light therapy would significantly decrease grehlin and increase leptin.

All light therapy groups beat the effects of sleep deprivation on hunger.

Despite sleep-deprivation, the blue and green light groups also had better hormone profiles than the well-rested group.

Red Light Reduced Ghrelin (Hunger) by 18.7%

Let’s compare the control group to the red light group.

  • The control group had 8 hours sleep, but no light therapy.
  • The red light group had 5-hours sleep, and 2 hours of red light therapy.

Here are the ghrelin hormones for both groups (ng/mL is nanograms per milliliter):

  • the well rested group had a median 945 ng/mL ghrelin
  • the sleep-deprived red light group had 768 ng/mL ghrelin

Compared to the well-rested group, the red light/sleep-deprived group had 177 ng/mL less ghrelin.

The red light group had an 18.7% better ghrelin reading than the well-rested group.

Red Light Ghrelin Improvement
8 Hours/
5 Hours
Difference
No Light
Red Light
ng/mL
Improvement
Ghrelin ng/mL
945
768
177
18.7%

Blue Light Reduced Ghrelin by 6.4%

Here are the ghrelin hormones for the well rested and the blue light therapy groups:

  • the well rested group had a median 945 ng/mL ghrelin
  • the sleep-deprived blue light group had 884 ng/mL ghrelin

Even though they were sleep-deprived, the blue light group’s ghrelin was 61 ng/mL lower than the control group’s. Blue light had a 6.4% ghrelin improvement.

Blue Light Ghrelin Improvement
8 Hours/No Light
5 Hours/Blue Light
Difference ng/mL
Improvement
Ghrelin ng/mL
945
884
61
6.4%

Green Light Reduced Ghrelin by 10.3%

Here are the ghrelin hormones for the well rested and the green light therapy groups:

  • the well rested group had a median 945 ng/mL ghrelin
  • the sleep-deprived green light group had 847 ng/mL ghrelin

Even though they were sleep-deprived, the green light group’s ghrelin was 98 ng/mL lower than the control group’s. Green light had a 10.3% ghrelin improvement.

Green Light Ghrelin Improvement
8 Hours/No Light
5 Hours/Green Light
Difference ng/mL
Improvement
Ghrelin ng/mL
945
847
98
10.3%

Red Light Increased Leptin (Fullness) by 19.3%

Here are the leptin hormones for the well rested and the sleep-deprived/red light groups:

  • the well rested group had a median 7.9 ng/mL leptin
  • the sleep-deprived red light group had 9.8 ng/mL leptin

Compared to the well-rested group, the red light/sleep-deprived group had 1.9 ng/mL more leptin.

The red light group had a 19.3% better leptin reading than the well-rested group.

Red Light Leptin Improvement
8 Hours/No Light
5 Hours/Red Light
Difference ng/mL
Improvement
Leptin ng/mL
7.9
9.8
1.9
19.3%

Blue Light Increased Leptin by 13.1%

Here are the leptin hormones for the well-rested and the sleep-deprived/blue light groups:

  • the well rested group had a median 7.9 ng/mL leptin
  • the sleep-deprived blue light group had 9.1 ng/mL leptin

The sleep-deprived blue lighters had a 1.2 ng/mL leptin jump. Blue light had a 13.1% leptin improvement.

Blue Light Leptin Improvement
8 Hours/No Light
5 Hours/Blue Light
Difference ng/mL
Improvement
Leptin ng/mL
7.9
9.1
1.2
13.1%

Green Light Increased Leptin by 5.9%

Here are the leptin hormones for the well rested and the sleep-deprived/green light groups:

  • the well rested group had a median 7.9 ng/mL leptin
  • the sleep-deprived green light group had 8.4 ng/mL leptin

The green light group had a 0.5 ng/mL leptin improvement. Green light had a 5.9% leptin improvement.

Green Light Leptin Improvement
8 Hours/No Light
5 Hours/Green Light
Difference ng/mL
Improvement
Leptin ng/mL
7.9
8.4
0.5
5.9%

Light Therapy Ghrelin and Leptin Tables

Here are all the improvements in ghrelin and leptin found in the study.

Red light beat all other conditions.

Blue light and green light both beat a full night’s sleep, but not as well as red light.

Leptin Results
Higher Numbers are Better
Condition
Median ng/mL
8 hours sleep, dim light
7.9
5 hours sleep, dim light
6.2
5 hours sleep, green light
8.4
5 hours sleep, blue light
9.1
5 hours sleep, red light
9.8
Ghrelin Results
Lower Numbers are Better
Condition
Median ng/mL
8 hours sleep, dim light
945
5 hours sleep, dim light
957
8 hours sleep, green light
847
8 hours sleep, blue light
884
8 hours sleep, red light
768

References

  • 904 nm Low-Level Laser Irradiation Decreases Expression of Catabolism-Related Genes in White Adipose Tissue of Wistar Rats: Possible Roles of Laser on Metabolism
  • Leptin signaling, adiposity, and energy balance
  • Infrared photobiomodulation (PBM) therapy improves glucose metabolism and intracellular insulin pathway in adipose tissue of high-fat fed mice
  • Prolonged REM sleep restriction induces metabolic syndrome-related changes: Mediation by pro-inflammatory cytokines
  • Insulin resistance is improved in high-fat fed mice by photobiomodulation therapy at 630 nm
  • Can low-level laser therapy (LLLT) associated with an aerobic plus resistance training change the cardiometabolic risk in obese women? A placebo-controlled clinical trial
  • The potential of phototherapy to reduce body fat, insulin resistance and “metabolic inflexibility” related to obesity in women undergoing weight loss treatment
  • [The influence of intravenous laser irradiation of the blood on the dynamics of leptin levels and the quality of life of the patients presenting with rheumatoid arthritis]
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