Dietary Fat, but Not Protein or Carbohydrate, Regulates Energy Intake and Causes Adiposity in Mice
The debate on the importance of different macronutrient configurations on body composition has driven many debates and fad-diets. In this new study in mice, published in Cell Metabolism, high dietary fat has been found to be the one diet that was associated with higher energy intake and adiposity.
The study, which involved the controlled feeding of mice 29 different diets varying from 8.3% to 80% fat, 10% to 80% carbohydrate, 5% to 30% protein, and 5% to 30% sucrose, also found an association with increased gene expression of different receptors in the brain. There was increased expression of 5-HT receptors, as well as the dopamine and opioid signalling pathways in the hypothalamus.
It has been documented that mice regulate their energy needs, and thus food consumption, based on caloric, as opposed to protein requirement. However, this study seems to suggest that this system can be compromised by hedonic factors linked to fat, but not carbohydrates. Although this is a long way from proving anything in humans, the shared similarities in energy regulation centres between the two species means that it is possible to speculate that humans share this hedonic factor override of energy regulation systems, which may provide an explanation to unhealthy eating behaviours such as binge eating.
Should we tax unhealthy food and drink?
According to the Proceedings of the Nutrition Society, after tobacco, unhealthy diets are the leading behavioural risk factor for all-cause morbidity and mortality in the UK. A poor diet can cause disease both directly via mediating factors such as weight-gain and hypertension, as well as potentially leading to CVD and T2DM through consumption of high-levels of saturated fat and highly refined sugar products.
Among children, 20% of 4-5 years and 33% of 10-11 year olds are either overweight or obese, with poorer children more than twice as likely to suffer obesity compared with children from affluent areas. It is clear, a new strategy is desperately needed if we want to protect the next generation from a whole variety of complex preventable diseases. Obesity is estimated to cost £6 billion per year in direct healthcare costs and a further £27 billion per year when losses in productivity are included. A key strategy for reducing the burden of disease involves trying to reduce overall consumption of unhealthy food, with taxation a primary component of the government’s plan.
There is a growing body of evidence from simulation studies, and other countries’ natural experiments, that sugar taxes can be effective at driving recipe modulation by industry, as well as behaviour changes amongst consumers. The indication is that fiscal measures are able to bring about desired price and purchasing changes to sugary drinks, while the weight of published data on sugary drinks taxes suggests that they will improve population health. However, the evidence is less clear on what the unforeseen outcomes of these taxes are; such as unhealthy recipe substitutions, or price equalisation between taxed unhealthy and untaxed healthy products by the manufacturers.
What is clear from the taxation strategies of other countries around the world is that the taxes need to be broad, intelligently designed, constantly evaluated to minimise unintended consequences, and overseen as to ensure that any loopholes for industry are discovered and managed. The economic costs of obesity are growing year on year and funding strategies must be developed in order to fund the treatment and care of overweight and obese individuals. In April 2018 the UK introduced an SDIL (Soft drinks industry levy). It involves taxing industry based on the concentration of sugar in their drinks using a 3 -tier system. The explicit aim of the tax is to change industry behaviour with regards to manufacture and reformulation, as opposed to trying to change individual behaviours.
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The Socio-economic Impact of Bariatric Surgery
This study, published in Obesity Surgery, aimed to generate real-world evidence of the socio-economic impact of bariatric surgery through evaluation of both its indirect and direct costs. Most studies focus on the direct healthcare costs only. However, this study used data collected over a period of 7 years from national registries, social transfer payments and income data, for surgically treated individuals, and compared them to that of a non-surgically treated individual, 3 years before and after surgery. The non-surgical group was defined as being eligible for bariatric surgery but not undertaking it.
The study found that there was a marginal increase in health-care costs in patients who underwent surgery, primarily because of the increased usage of in-patient services. It also found that there was a significant decrease in the costs of drugs, particularly anti-diabetic medication. Furthermore the study found that there a was notable positive effect of the surgery on social transfer payments; the costs of unemployment benefits were reduced and there were significantly higher social security payments.
Although this study was not able to identify net savings, it does not mean that bariatric surgery should be considered ineffective. The increase in health care-costs, mainly due to to complications and adverse effects of the surgery, should be weighted against the positive clinical effects that the patient will receive, namely reductions in prevalence of T2D and circulatory disease and medication to treat these, as well as considerable and sustained weight-loss which will enhance their quality of life and can also lead to a small decrease in total social transfer payments. Increased hospital care is a small price to pay for the sizeable benefits to the individual and society in the medium to long-term.
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The cost-effectiveness of OPTIFAST for the treatment of obesity
This study, published in the Journal of Medical Economics, assesses the potential cost-savings of using the OPTIFAST program in a population of US subjects, in comparison to “No intervention” and pharmacotherapy (liraglutide and naltrexone-bupropion).
OPTIFAST is a scientifically proven and medically supervised low-calorie diet program, for individuals with overweight and obesity. It has been shown to achieve acute and sustained weight loss, and reduction of clinical complications of obesity in studies since the 1980s. It involves providing obese patients with a 12 week diet of total meal replacement, with 2 subsequent phases of transition to a food based diet for 12 weeks each, and then another phase of 24 weeks. The total costs of the program is USD 4,500, which consists of USD 1,500 for the meals, and USD 3,000 for the weight management programme.
In the US at the moment, the threshold of willingness to pay for a new medicinal product per QALY is ~USD 50,000. A QALY is equal to one year of life lived in perfect health, and is calculated on numerous factors that assess quality-of-life systematically. This study has found that the cost of a QALY using OPTIFAST is USD 6,475, which is far below the threshold and represents great value for money. One of the reasons for this is the significantly lower incidence of complications, as compared with “no-intervention” and liraglutide or naltrexone-bupropion, in patients with class I or II obesity. This benefit is even more meaningful in class III obese patients with T2DM, and further increases with more time on the programme.
OPTIFAST has been demonstrated to lower healthcare costs, even when compared with bariatric surgery. Furthermore is has additional clinical and socio-economic advantages, due to few and mild adverse events when compared to other treatment regimes.
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Lifetime costs of obesity in childhood are growing
In this systematic review published in Paediatric Obesity, the authors sought to establish the costs of childhood and adolescent obesity in terms of direct healthcare costs as well as indirect productivity costs. Direct costs include drug costs, hospital in-patient costs, hospital outpatient costs and primary care costs. Indirect costs are divided into costs to society because of workdays lost and income penalty. Lost workdays accumulates the days lost to morbidity, early-retirement and mortality, whereas income penalty tries to assess how being overweight or obese may result in lower salary level.
Using 13 published research articles, they were able to work out that the average total cost was €149,206 for boys and €148,196 for girls. When this number was further broken down, it was found that lifetime cost was proportional to BMI, with lifetime costs increasing in proportion with excess weight during childhood or adolescence. It also found that productivity costs are significantly greater than healthcare costs, with girls being more likely to suffer increased healthcare costs and income penalties, and boys more likely to have increased work days lost.
An erroneous picture of the true cost obesity is created by studies which only focus on the direct costs of obesity. This study admits that the average figure, in the region of €150,000, is probably an underestimate due to the numerous costs which cannot be captured. This indicates a need for further research into the total excess lifetime costs of childhood and adolescent overweight and obesity, as only when this is properly evaluated can public health officials begin to allocate adequate resources.
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