Is Poor Sleep Leading to Weight Gain?

Aug 31, 2022

Have you ever had a night where you barely got 5 hours of sleep because of a pressing work deadline and then found that you were so hungry the next day and way too tired to exercise?  Diet and exercise programs usually dominate weight loss discussions, but there is a lot of evidence that sleep is just as important.

Sleep duration is falling

In the 1960s the average American slept 8-9 hours per night.  By 1995, it was down to 7 hours and today we are sleeping on average 6.8 hours per night. Today, over 35% of us are not getting the recommended 7 hours of sleep per night.

“Why should I waste 1/3 of my life sleeping?”

This is a question I hear so often.  During sleep, your body is working to support healthy brain function and memory consolidation while also helping maintain your physical health. Chronic sleep deprivation can impact immune system, carbohydrate metabolism, and endocrine function.  Insufficient sleep leads to increased risk of obesity, type 2 diabetes, coronary artery disease, hypertension, and premature death.

How can poor sleep lead to weight gain? 

Weight gain from poor sleep is due to a combination of factors.  Hormones involved in appetite and metabolism are impacted negatively by short-changing sleep. Poor sleep can lead to an increase in cravings and a desire for hyper-rewarding processed foods. Also, when someone is tired, they tend to do less physical activity, and this leads to a decrease in total energy expenditure.

Metabolic changes that may lead to weight gain include:

  • Increased insulin resistance (see last week’s blog),
  • Increased evening cortisol (cortisol is a stress hormone),
  • Increased ghrelin levels (ghrelin is a hormone that our stomach makes to tell us we are hungry),
  • Decreased leptin levels (leptin is a hormone our body fat makes to tell us we are full).

A few sleep facts:

  • Kids who sleep less than 10 hours per night are at an 89% greater risk to have obesity than their peers.
  • Adults who sleep less than 5 hours are 55% more likely to have obesity than those sleeping over 5 hours.
  • With 5 hours as a baseline, every additional hour of sleep decreased incidence of obesity by 30%.
  • In one study, 2 nights of 4 hours instead of 10 hours lead to an 18% decrease in leptin and 28% increase in ghrelin.

Some sleep tips:

  • Limit caffeine close to bedtime,
  • Watch alcohol consumption, which can disrupt deep sleep,
  • Get adequate natural light earlier in the day,
  • Establish a regular bedtime routine and make sure your sleep environment is comfortable,
  • Aim for 7-9 hours per night.  If you are currently under 6 hours you can slowly increase to this goal over time.

Talk to your primary care doctor if you are having trouble sleeping or if you suspect you may have sleep apnea!