Lifestyle and environmental factors such as stress, sleep, obesogens and probiotics, play a crucial role in weight gain.
Weight—too much of it, at least—is a major issue in Australia and, increasingly, worldwide. Most people are well aware of the importance of food choices and adequate exercise. Although more kilojoules-in versus kilojoules-out is part of the problem, there is mounting evidence that other lifestyle and environmental factors also play a crucial role.
Sleep the weight off?
While you may not literally be able to lose weight in your sleep, the fact is that lack of good quality sleep could increase weight gain.
Fewer hours = more weight
A study by Dr Siobhan Banks, Senior Research Fellow in the Centre for Sleep Research at the University of South Australia, found that people who slept less than four hours on average each night, for just five nights, gained more than a kilogram of weight, compared to those who slept 10 hours per night who gained no weight at all. And a 2008 study found that the odds of obesity were 2.3 times higher in women and 3.7 times higher in men for those not getting enough sleep.
How this works
Lack of sleep affects multiple hormones that play a role in food intake and the body’s ability to regulate appetite and sugar metabolism. Decreased insulin sensitivity (and therefore increased risk for type 2 diabetes); decreased secretion of leptin, a hormone that provides the body with the “I am full” signal; as well as increased output of ghrelin, an appetite-stimulating hormone, have all been shown with sleep deprivation. So skimping on sleep can pose problems for healthy weight management.
The sleep apnoea link
Another consideration is sleep apnoea, a condition that involves pauses in breathing while someone sleeps. These pauses can last as long as 30 seconds and happen multiple times over the course of the night. This ultimately leads to low blood oxygen levels and disturbed sleep patterns. While official figures for Australia are not available, it seems that prevalence rates are consistent worldwide with around one in four adults at risk of having or developing sleep apnoea. Risk of this condition increases with age and obesity, and is almost twice as likely in men as in women.
A vicious cycle
The relationship between obesity and sleep apnoea is a bit of a vicious cycle. Obesity increases the risk of sleep apnoea, but poor and interrupted sleep can also make it much harder to maintain a healthy weight. Having sleep apnoea properly diagnosed and treated is one way to start breaking this cycle. Treatment of sleep apnoea has been shown to help reduce visceral fat levels and elevated blood pressure and blood fat levels.
What you can do
Put simply, get more sleep. If you think you may have a sleep problem, such as sleep apnoea, talking to your health care practitioner is an important first step. Once a sleep disorder is diagnosed, and an effective remedy found to resolve the problem, weight management may prove much easier.
Gut-busting gut bacteria
Probiotics are well accepted for treating and preventing tummy upsets such as diarrhoea and constipation. As we study these friendly bacteria more closely, we are discovering many other hidden talents. Among these may be a role in helping us maintain a healthy weight.
Fewer bacteria = more weight
It turns out that these bacteria are important in our overall metabolism and that gut bacteria profiles differ quite a bit between obese and lean individuals. Both animal and human studies have found that obese individuals consistently have less diversity in their gut bacteria populations, with some species being either over- or under-represented compared to samples from lean individuals.
How this works
Preliminary investigations into how these differences could affect weight have found that imbalances in gut bacteria are associated with issues such as increased kilojoule extraction from food and increased inflammatory markers.
Emerging research shows promise
Supplementing certain probiotic species may be helpful. Although research in this area is just getting started, a small but interesting 2010 study found that supplementation of a specific probiotic (Lactobacillus gasseri) for a period of 12 weeks was associated with decreased body fat levels. This could pave the way for other studies to examine how specific probiotics may help support weight management efforts.
What you can do
So how do you change your gut bacteria to achieve a better balance? One way is to change what you (and therefore they) eat. High fat and sugar intakes have been shown to lead to imbalances in these bacteria, whereas more fibre and lower fat diets are associated with healthier profiles. Showing again that, when it comes to weight management, what you eat is as important as how much.
Are obesogens linked to obesity?
They may sound like something very exotic but “obesogens” (chemicals believed to increase risk of obesity) are all around us. In a relatively new area of obesity research, scientists are learning more about how chemicals in our environment affect our weight.
More environmental chemicals = more weight?
Examples of obesogens that have been identified so far include tetrabromobisphenol A (TBBPA), a flame retardant and tributyltin (TBT), whose uses include preventing growth of marine organisms on ships, docks and similar sites and as an industrial disinfectant.
How this works
Although how these chemicals promote weight gain is still being investigated, obesogens are known to disrupt the endocrine system and therefore affect various hormone levels and the way our bodies metabolise fats and other substances. Research on obesogens so far has shown effects such as
- an association between in utero exposure to certain chemicals, such as PCBs, and higher BMI later in life
- higher levels of urine metabolites of phthalates (used in plastics, and a possible obesogen) associated with wider waists and more insulin resistance in men
Emerging research
The effect of obesogens on human health largely remains to be seen, but research in this area continues. The OBELIX project is one such study. Started in 2009, OBELIX is looking specifically for links between early life exposure to endocrine-disrupting hormones and obesity later on in life.
What you can do
While it is difficult to avoid all of the potential obesogens in our environment, there are some steps that can help to reduce your exposure:
- Reduce pesticide exposure by eating organic when you can.
- Avoid plastic wrapped foods, plastic water bottles and plastic food containers.
- Choose natural personal care and household cleaning products.
Stress, hunger and obesity
We know that unrelieved and constant stress can have serious health implications. Many of us have experienced appetite loss when facing a stressful situation. But studies show that stress can also have the opposite effect—causing weight gain.
More stress = more weight?
Stress can play a major role in the amount and types of food that we reach for, and this can be seen from a very early age. Children with increased cortisol levels in saliva (one way to measure stress response) have been shown to be more likely to have higher BMI and to eat when not hungry. Teens with high amounts of academic (school study-related) stress have higher intakes of sugary junk foods than those with low levels of academic stress. ?
How this works
An important part of this stress-food puzzle is the hormone ghrelin. This hormone increases appetite and food intake (particularly high kilojoule foods) and has been shown to increase significantly in both animals and humans exposed to stress. Ghrelin also promotes the use of carbohydrates as an energy source while sparing fat stores, encouraging an increase and retention of body fat.
But don’t get angry at your ghrelin: it’s just doing the job it’s made for. We evolved in environments where food access could be inconsistent and predators lurked around every corner. Seeking out calorically dense foods and promoting fat storage helped to keep us alive until our next meal. Spikes in stress were usually associated with life or death situations. The trouble is, these days food in many countries is easily accessed and stress is chronic.
What you can do
Although what causes us stress now is not necessarily life threatening, our body still has the same set of hormonal responses it’s always had. Learning to manage stress can therefore be a powerful tool for maintaining healthier eating patterns, healthy body weight and reasonable body fat levels.
Weighing all the evidence
One of the most important first steps in overcoming weight issues is to address any underlying issues that can hinder healthy weight management, such as an underactive thyroid, polycystic ovarian disease, depression, anxiety or blood sugar imbalances.
Issues such as these can often be helped with natural interventions such as herbal or nutritional supplements administered by a knowledgeable health care practitioner. Fibre supplements that promote a feeling of fullness and reduce overeating can be helpful in some cases as well.
But in all cases, diet, exercise and lifestyle factors such as sleep and stress management need to be the main focus for long-term healthy weight; this is where the real and sustained changes are seen.
