It is known that short-term sleep deprivation increases plasma concentrations of ghrelin (a hormone related to increased appetite) and decreases those of leptin (a hormone related to satiety.)
In a randomized crossover study, researchers studied twelve normally healthy non-obese men to observe the effect of sleep deprivation on energy intake and physical activity. During the first night of each 48-hour session, subjects had either 8 hours (from midnight to 8:00 a.m.) or 4 hours (from 2:00 a.m. to 6:00 am. of sleep. All foods consumed thereafter (jam on buttered toast for breakfast, buffet for lunch, and a free menu for dinner) were eaten with no restrictions. Physical activity was also recorded. Sensations of hunger, perceived pleasantness of the foods, desire to eat some foods, and sleepiness were also evaluated.
In comparison with the 8-hour sleep session, subjects consumed 559 (22%) more calories on the day after sleep restriction, and hunger was higher before breakfast and dinner. Researchers observed no change in the perceived pleasantness of the foods or in the desire to eat the foods. Physical activity was slightly higher after sleep restriction than after 8 hours of sleep, even though the sensation of sleepiness was more apparent.
In this group of healthy men, one night of reduced sleep led to an increase in food intake and, to a lesser extent, physical activity-related energy expenditure. Although further research is needed to confirm the results of this small study, these results suggest that sleep restriction could be a factor that promotes obesity. B. Romer MA .
Go get some zzzzz's! :)
Showing posts with label Leptin. Show all posts
Showing posts with label Leptin. Show all posts
11.30.2009
Losing Weight...Let's Here it for Sleep!
Isn't it a beautiful thing, sleep?! But we don't get enough and more sleep may actually help take inches off your waist. Research shows that if you're sleep deprived, your body produces more stress hormones, which promote belly fat and also increase appetite. What's more, a new study shows that a sound night's sleep boosts levels of leptin, a hormone that works to suppress hunger. To study the sleep-appetite connection, researchers at Laval University in Quebec tracked the sleep habits of 740 men and women for 10 years. As it turns out, the benefits of just one extra hour of sleep are astonishing! The researchers found that women who got six to seven hours of sleep were 11 pounds heavier (men fared even worse—16 1⁄2 pounds heavier) than those who slept seven to eight hours a night. Blood tests revealed that short sleepers had levels of leptin 80 percent below those who got a full night of shut-eye.
So don't worry about being called lazy bones! You know a secret that helps you be thinner!
So don't worry about being called lazy bones! You know a secret that helps you be thinner!
10.29.2009
Leptin--Fat Hormone (cont.)
It is possible that having poor sleep habits may exacerbate leptin resistance because the 'sleep hormone' melatonin, appears to be closely related to leptin.
Many overweight individuals suffer from sleep apnea, a sleep disorder. This may cause them to Wake up regularly in the night, and melatonin production may become impaired, which then impacts leptin.
The goal is to increase your leptin production without gaining fat. It then may make the hypothalamus sensitive to it. Which is a good thing!
If you give yourself one day a week to have treats it can increase your leptin production while not gaining body fat. This is really helpful in preventing rebound weight gain that commonly follows a diet.
On this day where you allow yourself to have treats, only have 1 or 2 meals with anything you want to eat. Do not eat all you want all day long!! Increased calories from this day will prompt the fat cells to produce more leptin, which then tells the hypothalamus to reduce your appetite.
To prevent 'leptin resistance' you should:
Many overweight individuals suffer from sleep apnea, a sleep disorder. This may cause them to Wake up regularly in the night, and melatonin production may become impaired, which then impacts leptin.
The goal is to increase your leptin production without gaining fat. It then may make the hypothalamus sensitive to it. Which is a good thing!
If you give yourself one day a week to have treats it can increase your leptin production while not gaining body fat. This is really helpful in preventing rebound weight gain that commonly follows a diet.
On this day where you allow yourself to have treats, only have 1 or 2 meals with anything you want to eat. Do not eat all you want all day long!! Increased calories from this day will prompt the fat cells to produce more leptin, which then tells the hypothalamus to reduce your appetite.
To prevent 'leptin resistance' you should:
- Avoid excess sugar and 'bad fats'.
- Get regular daily exercise.
- Improve your sleeping habits.
10.26.2009
Fat Hormone #2: Leptin
Leptin is hormone produced by the fat cells. It is present in the blood stream and it is in direct proportion to the amount of body fat a person has, i.e. the more fat, the more leptin is produced.
Leptin's primary function is to ac on the hypothalamus, the part of the brain that controls appetite and satiety. It tells the hypothalamus to reduce appetite (because fat stores are high) , which results in decreased food intake.
But when the fat stores are low, like after dieting, leptin levels are reduced. This causes the hypothalamus to increase appetite. An increased appetite obviously results in greater food intake and a corresponding increase in body fat stores. More body fat results in more leptin being produced, which then tells the hypothalamus to decrease appetite, leading to a reduced food intake. This is a classic negative feedback mechanism.
Leptin my be one of the main hormones responsible for rebound weight gain after a diet.
Leptin is accurately described as an 'anti-starvation hormone' because low levels lead to increased hunger. In the past it was described as an 'anti-obesity hormone' but researchers have since discovered that obese people (who produce large amounts of leptin) are resistant to its action. Similar in the way that some people are resistant to insulin.
Leptin resistance can result from over-eating. When someone over-eats as a result of 'emotional eating' or a conditioned response' (a habit that has been created), the receptors in the hypothalamus become 'de-sensitized' to the action of leptin. This means that the hypothalamus can't detect when leptin levels are high, resulting in food cravings and further weight gain. Over time obesity is the result.
Leptin's primary function is to ac on the hypothalamus, the part of the brain that controls appetite and satiety. It tells the hypothalamus to reduce appetite (because fat stores are high) , which results in decreased food intake.
But when the fat stores are low, like after dieting, leptin levels are reduced. This causes the hypothalamus to increase appetite. An increased appetite obviously results in greater food intake and a corresponding increase in body fat stores. More body fat results in more leptin being produced, which then tells the hypothalamus to decrease appetite, leading to a reduced food intake. This is a classic negative feedback mechanism.
Leptin my be one of the main hormones responsible for rebound weight gain after a diet.
Leptin is accurately described as an 'anti-starvation hormone' because low levels lead to increased hunger. In the past it was described as an 'anti-obesity hormone' but researchers have since discovered that obese people (who produce large amounts of leptin) are resistant to its action. Similar in the way that some people are resistant to insulin.
Leptin resistance can result from over-eating. When someone over-eats as a result of 'emotional eating' or a conditioned response' (a habit that has been created), the receptors in the hypothalamus become 'de-sensitized' to the action of leptin. This means that the hypothalamus can't detect when leptin levels are high, resulting in food cravings and further weight gain. Over time obesity is the result.
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