The World Health Organization estimates that global levels of obesity have doubled since 1980. In 2012, more than 40 million children under the age of 5 were estimated to be overweight or obese, which is an issue of serious concern as excess body weight is believed to be the driver of many non-communicable diseases, namely type 2 diabetes, cardiovascular disease and some types of cancer.
To tackle what is, in most cases, a preventable condition, there is increasing focus on research into understanding the mechanisms behind obesity, including our genetics and the influence of lifestyle and the environment. There is also now increased focus on introducing public health initiatives to aid long-term weight loss, which range from improving public, patient and healthcare provider education to policy reform regarding the sale of pre-packaged and processed foods.
Which are the culprits – sugars, starches or fats?
How much of what we eat makes us fat? This is an ongoing debate, fuelled most recently by Robert Lustig and his focus on sugar. On the question of sugar, a further debate arises – is it sucrose or fructose that has the most impact on obesity?
In an editorial to introduce the article collection in BMC Medicine, Jack Winkler, former Professor of Nutrition Policy at London Metropolitan University, and currently Director of Food & Health Research, discusses why it is so hard to measure which food components are associated with obesity.
Prof Winkler explains one of the many problems with this field is that data derived from large-scale studies depends on reliable and consistent reporting. However, this is a limiting factor simply because these studies rely on self-reported energy intake surveys, and as Prof Winkler reminds us, people are good at lying about how much they are actually eating.
“The lies people tell about their food may be white lies, but they are large lies….. In one study of soft drinks, subjects in the National Diet and Nutrition Survey claimed to be drinking barely a quarter of the products that manufacturers reported they were selling”
The consequences of obesity
There is no question that obesity places a burden on healthcare services. Earlier this year, Gillian Reeves and colleagues showed that elevated body mass index (BMI) in UK women is associated with increased hospital admissions equating to around 420,000 extra admissions annually, indicating that current obesity levels are directly impacting UK healthcare services.
Primary care physicians are usually the first in line to treat patients with obesity related diseases, although patients may not be visiting their GP to directly ‘treat’ their obesity. As David Haslam, a GP and physician specializing in obesity at the Centre for Obesity research explains, the role of primary care in managing obesity is complicated in the UK by ineffective or contradictory policies. In his commentary published as part of this article collection, Prof Haslam starkly points out:
“Obesity prevention has failed. If nobody in the UK gains another single ounce, there are enough already obese people to make epidemics of diabetes, then heart disease then premature death inevitable.”
Prof Haslam, who also serves as Chair of the National Obesity Forum, highlights that obesity can be most effectively managed by individualization of care, which should be implemented through effective screening and risk management. After all, not all patients will benefit from weight loss. Prof Haslam discusses the obesity paradox in his commentary, and recent evidence on this includes a meta-analysis we published this year by Wie Nie and colleagues, showing that an obesity paradox exists for pneumonia – i.e. obese individuals have an increased risk of pneumonia but a decreased risk of pneumonia mortality, indicating a survival advantage for obese individuals.
However, in most cases, obesity and diet are considered as a causal risk factor for chronic diseases such as type 2 diabetes. Recently, Elin Hall and colleagues showed that exposing pancreatic islet cells to the free fatty acid palmitate results in differential gene expression and epigenetic modifications, which may influence type 2 diabetes risk through impaired insulin secretion in these treated cells.
In an Opinion article, Naveed Sattar and Jason Gill discuss the plausible link between type 2 diabetes and ectopic fat around organs such as the liver and pancreas. In their article, they explain that studies have shown accumulation of ectopic fat around the liver leads to insulin resistance, and they also hypothesize that fat around the pancreas could lead to β-cell dysfunction. Prof Sattar and Dr Gill ask a very provocative question: can type 2 diabetes be reversed by loss of ectopic fat around key organs?
Taking action on obesity
So, what should be done about the rising levels of obesity? One of the physicians leading the issue is John Wass, a consultant physician and endocrinologist, and also Chair of the Working Party for Action on Obesity.
I interviewed Prof Wass about the goals of the working party, which aims to tackle the rise of obesity in the UK by filling current gaps in knowledge and support within the healthcare and medical education systems. Prof Wass highlights that educating the public about healthy eating, and collaborations with the food industry on how to responsibly sell and label foods, is key to improving public health.
There is also ongoing debate about whether or not obesity should be considered as a disease. On this, Prof Wass explains that as obesity is a condition that needs to be actively managed it can be labelled as a disease, and unless it is recognized as such, prevention and management strategies will not be taken seriously.
The good news is, research into the causes and consequences of obesity is now a major global research and public health focus. So, perhaps hope is on the horizon to successfully curb the obesity epidemic.
These articles appear in our Obesity: exploring the causes, consequences and solutions article collection. We are seeking submissions of articles covering all areas of obesity research, including clinical studies of new therapies and interventions, epigenetics and translational advances that contribute to understanding the causes and impact of obesity. If you have any research you would like us to consider for inclusion in this article collection, please email firstname.lastname@example.org
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