Could a lack of sleep be making you fat? UPDATE

Since I wrote about this in May 2010, a new research study has come to light that reinforces my earlier conclusion – that your sleeping habits could be to blame for those extra pounds.

The research study, “Sleep problems and major weight gain: a follow-up study” by P Lyytikäinen, T Lallukka, E Lahelma & O Rahkonen (published online in the International Journal of Obesity on 8 June 2010), shows that middle-aged women who have trouble sleeping are more likely to gain weight than those who sleep well.

The study followed over 7,300 middle-aged (40 to 60 year old) women and men for five to seven years. The researchers found that the women who had reported suffering from “frequent sleep problems” (trouble falling asleep or staying asleep on at least 14 nights in the past month) at the start of the study were more likely to report a “major weight gain” (11 or more pounds) over time than the women who slept without difficulty. Even when other factors, such as physical and mental health and lifestyle, were taken into consideration, the link between sleep problems and major weight gain remained – for the women, anyway.

Strangely, there was no association found between the men with troubled sleep and major weight gain, however. Whilst the reason for this difference is unknown, it’s possible that the fewer male participants (1,300 men compared to more than 5,700 women) could have made the link more difficult to spot.

Lead researcher, Peppi Lyytikäinen, told Reuters Health that while the findings do not prove cause-and-effect, they raise the possibility that improving sleep quality might help stave off excess weight gain.

How to cope with early starts

The Sleep Geek: A man in glasses who knows a lot about sleep

Rising earlier than usual often means getting less sleep than usual. In addition, the thought of getting up early can cause stress and worry, making falling asleep more of a challenge. The result of an early start is typically fatigue, lethargy and increased appetite. Simply put, you feel rubbish and want to eat rubbish.

Thankfully there are some simple ways to make an early start a little easier. The Sleep Geek has helpfully shared his tips for handling early mornings in his new article “Early Starts and Little Naps” – read it by clicking here.

Could a lack of sleep be making you fat?

I spent the weekend in the lovely English countryside with my other half. It was wonderful….until 5am yesterday morning when we had to drag ourselves out of bed – after around five and half hour’s sleep – and drive back to London for my other half’s 7am start time.

After the initial shock of getting up in the middle of the night (it felt like that, anyway) I felt exhilarated by my early start. The sun was coming up as we drove and by 6:30am I was in London and ready to start my day, having already listened to the morning news on the way in.  I’ll admit it, I felt rather smug.

Things started to go downhill at about 9am. I suddenly felt tired and lacking in energy. Despite my usual daddy-bear-sized bowl of porridge only a few hours earlier, I also felt very hungry. I wanted thick white toast smeared with butter and jam. And Crunchy Nut Cornflakes. And chocolate biscuits.

I managed to get through the day, succumbing to my rumbling stomach only once or twice more than usual. It took sheer determination to stop myself from finishing off the box of Maltesers in the cupboard though.

I mentioned my increased appetite to my other half, after polishing off three large chicken fajitas for tea last night. He, too, had felt especially hungry that day – although he is constantly hungry so I’m not sure how remarkable that is!

I reflected on our conversation later that evening. Was our greediness that day a consequence of our lack of sleep the night before?

First thing this morning – after an early night and a glorious eight hours of sleep – I did a spot of research. And there was my answer in black and white: according to a number of scientific studies, a lack of sleep increases feelings of hunger, which can lead to eating more and gaining weight.

I found three 2004 studies[1], that had all found a link between sleep and the hormones that are involved in regulating appetite – ghrelin, which makes you feel hungry and leptin, which suppresses appetite. These studies found that people who slept for shorter durations had increased ghrelin levels and reduced leptin levels. Wow!

One of these 2004 studies, reported in the Annals of Internal Medicine, also found that sleep deprivation affects our food choices. In that study, when sleep was restricted, the participants craved calorie-dense foods with high carbohydrate content.

In a recent study, reported in the American Journal of Clinical Nutrition in March 2010, the participants (healthy, normal-weight young men) took in 22% more calories, on average, when they’d slept for four hours the night before, compared to when they slept for eight hours. The average calorie increase after a night of restricted sleep was about 560, equivalent to a Dominos cheese and tomato pizza!

This is fascinating! The results match my own experience completely – increased appetite, craving carbs and eating more calories than normal. What an eye-opener.

So, the next time you’re feeling extra peckish, consider whether your sleeping habits could be to blame. And, if you’re trying to lose weight, getting some more quality sleep could be the key to shifting those pounds!


[1] Karine Spiegel, PhD; Esra Tasali, MD; Plamen Penev, MD, PhD; and Eve Van Cauter, PhD (7 December 2004)“Brief Communication: Sleep Curtailment in Healthy Young Men Is Associated with Decreased Leptin Levels, Elevated Ghrelin Levels, and Increased Hunger and Appetite”, Annals of Internal Medicine, vol 141: pp 846-850

Does the lack of sleep make you fat? (7 December 2004) Bristol University Press Release

Shahrad Taheri, Ling Lin, Diane Austin, Terry Young, Emmanual Mignot (December 2004) Short Sleep Duration Is Associated with Reduced Leptin, Elevated Ghrelin, and Increased Body Mass Index Public Library of Science Medicine