Diets don't work: Is changing the clocks making you tired, fat and lethargic?

Diets don't work: Weekend warrior as good as daily gym bunny

Adam Atkinson

Our Diets don't work blog is by Ascot-based personal trainer Adam Atkinson. He offers health and fitness advice on our websites each month.

If over the past few days you have been feeling perhaps a little tired, and more than likely hungry, then don’t worry. You’re not alone and there is most likely a reason – the change from BST to GMT as we put the clocks back one hour.

Although one hour’s difference may seem small, it’s enough to disrupt sleep and your hormonal balance making it really hard to sleep well, eat healthily and feel good about yourself. 

It’s not just the changing of the clocks either. Because of the Earth’s elliptical orbit (a squashed circle), the increase and decrease in daylight over the year is not uniform. This is why it just doesn’t seem to get lighter during January, even though we know the shortest day is long gone. Because of the Earth’s orbit, the change in daylight at this time is very slow, only around a minute per day. Yet come March, this increases to almost 4 minutes per day. In just the same way, darkness is coming at its fastest rate in late October. So not only is it getting dark quickly, but changing the clocks adds a sudden and dramatic increase to this darkness.

So if you’ve been feeling blue, hungry (particularly for fatty sugary foods), tired and lethargic, then this may be why. The increased darkness and sudden clock change actually has many detrimental health effects.

An increase in depression. A Danish study of 185,000 people who suffered from depression found that the condition rose by 11 per cetn when the clocks went back in autumn. Sometimes known as SAD (seasonal affective disorder) this condition can also affect normal, happy healthy people, making them feel a bit down and out of sorts. Sound familiar?

An increased risk of heart attack and stroke. Other studies have shown that the risk of heart attack and stroke increases when the clocks go back - researchers suspect this is caused by sleep loss, increased stress and reduced time for cell repair and recovery overnight. Happily, this increased risk of a heart attack only lasts two weeks. After that, our biological clock synchronises to the new time.

Disruption of your circadian rhythm. This is the cycle our body uses to determine when to sleep and when to be awake. Amounts of the hormone melatonin, which makes us want to sleep, are suppressed by light. Less light, more melatonin. So most of us will have a greater tendency to feel tired and lethargic.

Increased hunger. Tiredness also encourages production of cortisol, our stress hormone. This will make us crave fatty and sugary foods. Add in the colder temperatures and our survival instinct can make us want to eat more than usual – anecdotal evidence from our 14 years as personal trainers shows this week to be a particularly difficult one to lose weight. Science agrees; a study of 593 people from the University of Massachusetts showed that in the autumn participants ate on average 86 calories a day more than in spring. Added up over the course of a week and this equates to around ½ pound of weight gain. Over the whole winter this could see you putting on 7lbs or more.

Vitamin D deficiency. Vitamin D is responsible for bone health, brain development and function; we get vitamin D mainly from sunlight. As the days get shorter some adults can become deficient in the vitamin; this deficiency shows up in common health conditions such as constant coughs and colds, tiredness and fatigue, poor bone and tooth health and low mood.

So how can you combat these darkness induced health problems? Exercise, socialising as much as possible and getting outdoors as often as possible will help with both seasonal blues (SAD) and vitamin D deficiency. The latter can also be helped by eating foods rich in vitamin D and also foods containing good fats – vitamin D is fat soluble, and can only be used in the presence of fat. So oily fish, oranges, red meat, cheese and tofu will all help. Eating more protein and foods that are filling (like vegetables, soups and healthy stews) will help to control hunger. Drinking low calorie drinks like tea and coffee can also keep you full, as will drinking more water.

Trying to get regular sleep is also important, with consistent bed and waking times. SAD can also be helped by light box therapy – sufferers sit in front special lamps that mimic daylight for short periods during the day. Increased chances of heart attack and stroke can of course be countered by healthy eating, regular exercise and as with other clock change problems, proper sleep.

Adam Atkinson 

07830 148300/0800 0407526