THIS must be the worst time of year to write about weight loss. It’s a week before Christmas and we’re surrounded by mince pies and chocolates. Do bear with me though; this isn’t what you might think. Last week I finished an excellent and enlightening book called Why We Sleep by Professor Matthew Walker. The book explores the whys and how’s of sleep and discusses the huge impact of poor sleep on health. Most interesting to me are studies done on sleep and food choices – namely, the unhealthy choices we make after a bad night’s sleep.

The research is clear: sleeping less than six hours a night increases your chances of gaining weight, being obese, and developing Type 2 Diabetes. Not getting a full 7-8 hours of sound sleep increases appetite, reduces feelings of satiety, and makes you more likely to impulsively eat sugary starchy snacks like cakes and crisps.

These research findings are hugely significant. How many of us can safely say we consistently get 7-8 hours of sleep?

Add in the fatigue and lack of motivation to exercise caused by poor sleep and you have the perfect combination for weight gain and pre-diabetes problems.

The mechanisms for these effects are fascinating. Firstly, poor sleep affects levels of our appetite hormones leptin and ghrelin. Ghrelin is the hunger hormone, and leptin tells us when we are full. Poor sleep causes ghrelin to increase and leptin to fall, causing us to eat more and not recognise when we are full.

Secondly, the part of our brain responsible for thoughtful decision making is less active when we’re tired, making us more impulsive and likely to give in to cravings for sweet starchy foods.

No matter what diet plan you follow, if you aren’t sleeping enough you are unlikely to achieve sustainable long-term weight loss. So, rather than a miserable New Year detox, think about how to improve your sleep. Stop using gadgets and television at least an hour before bed and keep the bedroom dark and cool. Set consistent sleep and wake-up times; the human body loves rhythm and routine, particularly around sleep. Give yourself the gift of more sleep for Christmas; it’s the best thing you can do for your waistline.

Sally Duffin is a Registered Nutritionist (MBANT). Find her online at or join the Facebook group ‘Nutrition in York’.