Why Adequate Sleep is Important for Weight Loss
Sleeping less would seem to help you lose weight because, when awake you burn more calories than when you are asleep. This should apply whether you voluntarily choose to sleep less or your sleep is very disturbed or you have sleep apnea.
However, recent research has shown the opposite. Getting a good night's sleep helps when people are trying to lose weight.
People who are deprived of sleep do burn more calories, but this is more than offset by eating more, and eating the wrong types of food for the wrong reasons.
Tired and stressed people tend to eat for comfort, or to relieve stress not because they are hungry. Also sleep deprivation has been shown to induce major changes in fat metabolism that contributes to weight gain.
This article reviews the latest research on:
- Sleep apnea and weight gain
- Sleep deprivation and weight gain
Do Night-Owls Who Sleep Less Burn More Calories?
Yes they do!
Studies have shown that people who only sleep five hours a night burned an extra 110 calories per day. This is equivalent to about one quarter of a regular size meal.Do Night-Owls Who Sleep Less Eat More Food?
Yes they do!
Energy intake (calories consumed) was much greater, especially late at night, well after dinner.
The extra energy intake is well in excess of what was needed for the extra calories burnt by sleeping less.
Sleep deprived people may be less active and less inclined to exercise as well.
Studies showed that when food was readily available, food intake surpasses what was needed.
Night-owls may eat not to overcome hunger but because they are stressed.
Do Night-Owls Who Sleep Less Gain Weight?
Yes they do!
Scientists from the University of Colorado studies eight changes of 16 healthy women and men over a two-week periods of strictly controlled conditions.
During week one, 8 of the subjects were allowed to sleep 9 hours and the other eight only 5 hours. Each group was given access to plentiful food that as not restricted.
During the second week the two groups swapped sleeping patterns with the night-owls swapping to 9 hours of sleep and vice versa.
Over the course of the study, both groups that had only 5 hours sleep gained an average of about 1 kg (2 pounds).
The sleep deprived subjects ate far more and gained weight.
Does Sleeping Less Change the Type of Food Eaten?
Once again the answer to this is: "Yes!"
In the study there was always plenty of food available and the food eaten was carefully monitored.
The Night-Owls ate far more carbohydrates.
They had tiny breakfasts and huge quantities of snacks late at night, after dinner.
The Night-Owls ate an average of about 10% more calories when sleeping only 5 hours a night.
Were the Changes in Diet and Meals Reversible?
Once the Night-Owls swapped to sleeping longer they resumed their healthier eating habits and started to lose the extra weight.
The researchers also found that lack of sleep also changed the person’s internal clock and this affected their eating and sleeping patterns.
Do Children and Adolescents Who Sleep Less also Gain Weight?
Yes they do!
Other studies have shown that children who sleep less than 10 hours a night gained weight.
A study of more than 8,000 British children who were monitored from birth, found that those who slept less that 10 hours a night,when aged 3 years, had about a 50% greater risk of becoming obese by the age of 7 years.
A study of almost 1000 American children, found that those that slept for less than 12 hours a night had twice the risk of being obese at 3 years of age.
A New Zealand study of more than 1000 children, from birth until age 32, found long term effects of sleep deprivation.
The study found that lack of normal sleep duration during childhood (3- 9 years) increased the risk of obesity at age 32 by 50%.
Do Other Studies Confirm the Conclusions that Sleep Deprivation leads to Weight Gain?
For adults the results of various studies have shown similar results.
A major study of 68,000 middle-age American women for 16 years, showed that women who slept less than 7 hours a night were 15 % more likely to become obese over the course of the study.
How Does Sleep Deprivation Cause Weight Gain?
There appear to be several mechanisms:
- Poor Diets - As outlined above sleeping less leads to eating more carbohydrate snacks and other foods late at night. Sleep deprived people have less healthy diets.
- Increases in Hunger - There are suggestions that sleep deprivation may affect the hormones that trigger hunger.
- Eating for the Wrong Reason - People are more likely to eat, not because they are hungry but because they are stressed and need 'comfort'
- Changes in Fat Metabolism - Sleep deprivation has been shown to make the fat cells less sensitive to insulin. These metabolic changes are associated with both obesity and diabetes.
- People who are wake for longer have more time to eat - People who are deprived of sleep tend to snack more, sometimes to keep them awake
- Reduced Physical Activity - People who sleep less tend to be exhausted during the day and late afternoon and show no enthusiasm for exercise.
- Lowering the body temperature - In various studies, sleep-deprived people tend to have slightly lower temperatures which may lead to decreased energy expenditure.
Sleep Apnea and Weight Gain
Results of various studies show that people with sleep apnea tend to have a higher BMI and they gained weight over time due to lack of proper and adequate sleep. The apnea ruins the qualify ogf their sleep as well.
Does Lack of Sleep Stop Weight Loss Progress When Dieting?
For anyone who thought that you could just sleep away that excess weight, was not dreaming because it is partially true.
People who sleep less than 8 hours a day are more likely to put on weight.
Increasing the amount of time you sleep by a few extra hours can actually help you lose weight.
There is a lot of research that supports these ideas, but other factors complicate the situation, as other things linked with hours slept may also contribute.
A research study done at Columbia University found that:
- People who only sleep 2-4 hours a night were about 75 % more likely to be obese than normal sleepers.
- People who slept 5 hours a night were 50 % more likely to be obese.
- People who slept 6 hours a night were found to be were about 25 % more likely to be obese.
- Long sleepers who sleep for more than 10 hours were 11 % less likely to be obese.
Although the exact mechanism is unknown and the results are only associations, not a cause an effect, the study seems to suggest that having more sleep provided a protective effect reducing the risk against obesity.
It is equally likely that obese people tend to sleep less and this produces the association found in the study.
These results generally confirm other studies of adolescents and children that show a similar relationship between sleep and obesity for these groups.
There are various theories to explain this that range from a tendency for sleep deprivation to encourage poor diets and binge eating, lack of exercise, changes to the body clock and the way the body processes food and hormone changes.
The amount of sleep may impact various hormones that affect food intake and appetite, such as "leptin and ghrelin," according to this research.
Various researchers have found that students deprived of sleep tended to be
- were less alert and slovenly
- hungrier
- had increased amount of body fat, especially belly fat
- ability to metabolise sugar was reduced
- had lower levels of the hormone leptin (a protein manufactured by your body’s fat cells). People carrying higher fat loads tend to have higher the level of leptin in their bloodstream. Researchers are still unclear exactly what leptin does in the body but think it may help generate feelings of satiety and fullness after eating or it may affect appetite.
- had higher levels of ghrelin which is a hormone that triggers hunger. Lack of sleep induces hunger and encourages people to eat more.
- people tended to be fatigued and this lead to them wanting to eat to get the sugar fix.
A major Australian study examined the relationship between sleep and obesity for children aged 5 to 15 years. The association between short sleep and obesity was strongest for younger children, especially boys.
The study showed that the association was insignificant for children aged 13-15. The study also showed that the impact of short sleep was compounded by low levels of physical activity.
A Japanese study involving over 2600 non-obese male workers (aged 40-59) was designed to show whether dietary patterns explained the association between short sleep duration and obesity.
The findings were that the preference for snacking, skipping breakfast, fatty food and eating out by people who were sleep deprived only partially explained the association with obesity. The researchers suggested that other things, including physiologic mechanisms and hormones, may explain the association between sleep and obesity.
A Swedish research study found that sleep-deprived young men consumed about the same amount of food as a control group who slept normal hours, but burned between 5-20% percent fewer calories than the well-rested group.
The sleep deprived young men were more fatigued and exercised less that the group who slept more.
Another study of 30 men and women divided into two groups, who had controlled amounts of sleep of 4 and 9 hours, showed similar calorie consumption rates of about 2,600 per day. But the sleep-deprived group, when allowed to feed themselves ate about 300 more calories on average than when they had been sleeping normally.
This meant that the sleep deprivation increased the risk of obesity. The subjects in this study reported that they felt less energetic and more sluggish after a few days on the sleep-deprivation schedule.
One possible explanation is that when people are tired they become vulnerable to making poorer healthy eating decisions.
This especially applies to people who are on diets or who are trying to watch what they eat.
CONCLUSION - Sleep Deprivation is Linked to Weight Gain
Increased food intake by sleep deprived people appears to be a physiological and behavioural adaptation to provide extra energy to keep awake longer and to provide 'comfort'.
It is clear that sleep plays a key role in energy metabolism in many ways and the amount of sleep contributes to the risk of weight gain and obesity.
