Is diet and exercise enough to stop us gaining weight? This is the question that Dr Berit Heitmann, obesity researcher from the Institute of Preventive Medicine in Copenhagen, presented to us at a talk she recently gave in Sydney. And her short answer? No.
Having looked at all the studies to date including two Cochrane reviews she found that on average these diet/exercise interventions helped people to eat more healthy food and do more activity but had little or no effect on weight. So what else could it be?
How long will you lie there you sluggard? When will you get up from your sleep? A little sleep, a little slumber…and poverty will come on you like a bandit. Proverbs 6:9-11
Most cultures have wise sayings about the negative result of being lazy or sleeping too much. But in today’s culture we seem to have the opposite problem – not enough sleep. Stress, computers, television, long work hours and burning the candle at both ends are just some of the habits that steal our sleep – and it’s making us fat.
Sleep is not optional, it’s essential to good health. While we sleep our body releases substances that fight infection, build and repair muscle, control appetite, consolidate memory (remember this if you are studying) and promote maturation in teenagers.
Lack of sleep makes our body work differently. It reduces insulin sensitivity and alters two key hormones: leptin and ghrelin. Leptin reduces hunger so it’s good to have plenty around. But lack of sleep, especially when combined with stress, drops those appetite suppressing leptin levels.
If you’ve decided to cut back on bread in an attempt to control weight, think again. Wholegrains were one of a handful of winning foods in a new study looking at long term weight control. The researchers from Harvard Medical School and Harvard School of Public Health found that people who ate more wholegrains actually gained less weight over four years.
Published in the New England Journal of Medicine this study of over 120,000 people found that people who ate more unprocessed foods, specifically wholegrains, nuts, yoghurt (reduced or full fat), fruit and vegetables gained the least weight over a four year period.
These people didn’t just keep on eating the same amount over the four years; they actually increased the number of serves of these foods they ate each day. More food means more kilojoules so why didn’t they gain weight? These foods are all high fibre (apart from yoghurt) nutrient rich foods which provide long lasting satiety. They keep blood sugars stable without the rapid spikes that experts now think contribute to weight problems. If you eat lots of these foods chances are you won’t feel quite so desperate to munch on crisps or slurp on a soft drink.
Eat less, exercise more. Weight loss is a simple equation, or is it? Recently at the Australian Institute of Food Science and Technology conference I was intrigued to hear a number of speakers mention how the type of bacteria living in our digestive system can influence our weight.
Does that mean if I eat a whole lot of probiotic yogurt I will magically lose that extra padding around my stomach? It’s not quite that simple.
Our digestive system is teeming with microorganisms. In fact our body contains more bacteria than cells. We have around 10 trillion cells but around 100 trillion bacteria. In recent years scientists have discovered just how essential they are for health including:
- stimulating the immune system
- breaking down toxins and carcinogens in food
- fighting against bad bacteria such as e.coli, salmonella and clostridia
- fermenting food to release and absorb nutrients
- regulating inflammation
- regulating energy uptake from the gut