A glass of water a day keeps obesity away?
Drinking 500ml of water half an hour before eating meals may help obese adults lose weight. A study conducted at the University of Birmingham on 84 obese adults showed that this simple intervention could be profoundly beneficial. The group was randomly split into two, and both were given a weight management consultation, to discuss how best to adapt lifestyle and behaviour, in order to promote weight loss. 41 were asked to “preload” with water before eating, whilst the others were told to imagine their stomach was full.
The participants were monitored over a 12 week period, and those that were asked to drink water before their main meal lost, on average, 1.3kg more than those in the control group. Those who preloaded 3 times a day lost 4.3kg! The intervention was simple and was shown to be effective at follow-up. We must bear in mind though that it was not only filling up on water before meals that resulted in weight loss, each participant was given lifestyle advice. The researchers hope to continue their research on a larger population in the future.
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Bad news for first born sisters…
Older sisters are more likely to be overweight and obese when compared to their younger siblings. According to a large study performed on 13, 406 Swedish sister pairs. The results corroborate with previous studies that found older brothers to be both, heavier, and taller, than their younger siblings. The study showed that at birth, firstborns weighed a little less than the second born sisters, however their BMI was around 2.4% higher during their first 3 months of pregnancy.
Overall it was found that firstborn women were 29% more likely to be overweight, and 40% more likely to be obese during their mid-20s, furthermore they were an average of 1.2mm taller. Sisters with a high number of siblings were also more likely to be shorter and the researchers hypothesised that this could be due to a phenomenon known as ‘resource dilution’ – the idea that parental resources are spread more thinly across a higher number of children.
It was unclear why older sisters seemed to be heavier, however the researchers hypothesised that changes in the womb after the first pregnancy could be a potential cause. It is possible that during the first pregnancy, blood vessels are narrower in the placenta, limiting flow. The body then adapts to this to store more fat and glucose. For subsequent pregnancies the blood flow is altered to stop this from happening. Although the findings confirm the results in other studies involving men, more research is needed to see whether there is an associated increase in metabolic risk in first born women.
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Does a feeling of reward cause obesity?
A French team have examined the role of pleasure when compared to that of energy needs in food intake. The study was performed on a group of mice and considered the activity of neurones that regulate feeding behaviours, known as NPY/AgRP. These are activated in periods of fasting and promote food intake. They found that these neurones become dispensable when a highly palatable diet is chosen; instead the hedonic circuitry in the brain drives the feeding behaviours. However when food is not palatable, it is the AgRP neurones that drive feeding in response to the body’s metabolic needs.
Using these findings it was shown that animals with compromised AgRP neurone activity could be more prone to comfort eating as they are more likely to consume palatable food due to stress. The mice with compromised AgRP neurones were also more sensitive to external factors, such as stress, they were therefore very good models for comfort eating.
A continued exposure to palatable foods, many of which are energy-rich could alter NPY/AgRP circuitry and cause them to become desensitised, leading to the reward circuit taking over. Overall, these results shed more light on the energy balance mechanisms controlled by NPY/AgRP and highlights how the reward circuitry interacts with it and may explain why people can’t seem to avoid eating the wrong foods!
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Is weight loss surgery altering gut bacteria?
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Bariatric surgery before pregnancy – Is this a solution to a big problem?
In the UK, 33% of pregnant women are overweight or obese and may experience gestational diabetes. Bariatric surgery commonly leads to greater and more sustained weight loss than do lifestyle approaches, and evidence that bariatric surgery can prevent, treat, or even “reverse” type 2 diabetes has increased enthusiasm for its use prior to pregnancy. However, there are also concerns that potential malnutrition or malabsorption resulting from these surgeries may lead to pregnancy complications.
In this article from America, pregnancy outcomes were examined in women from 2006 to 2011 who underwent bariatric surgery prior to pregnancy as compared with matched controls. (Early-pregnancy BMI in the control cohort was matched to pre-surgery BMI in the bariatric-surgery cohort). As compared with controls, women with a history of bariatric surgery had significantly lower incidences of gestational diabetes.
Obstetricians will most likely be seeing an increasing number of women who have undergone bariatric surgery before pregnancy although women are advised to delay conceiving until 12 to 24 months after surgery. But the current data, combined with previous reports, suggest that it may be prudent to monitor foetal growth in women who have undergone bariatric surgery, particularly in those who have had gastric bypass surgery.
The current study underscores that bariatric surgery has the potential to reduce the risks of gestational diabetes and large-for-gestational-age neonates but is also associated with some risks in pregnancy such as preterm birth, stillbirth, neonatal death, and major congenital malformations. Decisions regarding bariatric surgery in women of reproductive age should take into account the benefits and risks associated with this, not inconsequential procedure in terms of both pregnancy and long-term health.
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New function of obesity gene revealed
In research published by the New England Journal of Medicine, scientists at Harvard and MIT found that by tweaking certain pieces of the DNA code in the gene region responsible for coding the fat mass and obesity-associated protein, known popularly as the “FTO gene” or the “obesity gene”, they could cause the body to accelerate metabolism and burn excess fat that otherwise would have remained stored.
The FTO region harbours the strongest genetic association with obesity, yet the basis of this association remains elusive. To test how faulty genetics were at play in weight gain, the researchers took fat samples from Europeans holding both the variant of the FTO gene region linked to obesity and a normal FTO gene. They discovered that, in those with obesity, the DNA code of the FTO gene was activating two other associated genes, IRX3 and IRX5. Those genes, in turn, were preventing fat from being burnt through a process known as thermogenesis, where fat cells get rid of energy in the form of heat, instead of storing it as fat. This happens naturally in those with healthy FTO gene regions.
Testing on mice using the Crispr/Cas9 system, which edits the faulty DNA code to the correct sequence, the scientists were able to install the correct code, thereby preventing the body from storing excess fat. The process has so far proved successful in reversing obesity in mice, but is yet to be tested on humans.
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Chillies becoming hot topic in fight against obesity
Researchers in Australia have investigated the association between hot chilli pepper receptors (TRPV1) and the feeling of fullness in mice. As the stomach fills it begins to stretch, which activates nerves that inform the body that the stomach is filling and when it has reached capacity. The researchers found that this activity is regulated by TRPV1 receptors, also known as hot chilli pepper receptors. This builds on previous knowledge that capsaicin, the chemical that makes chillies hot, reduces food intake in humans.
The study also found that deletion of TRPV1 receptors dampened the response of gastric nerves to stretch. This resulted in a delayed feeling of fullness and consumption of more food, showing that the capsaicin mechanism is potentially vital in controlling how much food we eat. Dr Stephen Kentish, one of the study authors, hopes to ‘see how feasible this is as a potential treatment not just for obesity itself but maybe in the prevention of gaining weight.’ These exciting findings could inform further research in this area and lead to the development of novel therapies.
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Anti-fat bias from teachers
Obese people are often the target of stigmatisation and discrimination, they are sometimes stereotyped as lazy and unmotivated. There has been research into these kinds of behaviours towards adults, however the extent of weight stigmatisation amongst children in schools has received less attention. A recent report, carried out at the University of Newcastle in Australia, has shown that physical education (PE) teachers have strong anti-fat biases. The study tested 240 trainee PE teachers and non-PE trainees for explicit bias – negative views that they admitted – and implicit bias – using techniques such as word association to see what perceptions they associated with overweight.
Whilst many schools continue to encourage children to lead healthy lifestyles, the evidence shows that the raised awareness of obesity may actually be increasing the stigma associated with it. Interestingly, the study also showed that the trainees almost expect the children to underperform, even in things that don’t have anything to do with obesity, such as verbal reasoning skills. The study was unable to determine whether the teachers entered their programmes with pre-formed bias, or whether the bias developed over their time in training. School teachers directly influence their children’s behaviours and self-esteem, and this report highlights the fact that schools need to evaluate whether anti-fat bias exists within its staff. If the results are affirmatory, then appropriate staff development programmes need to be created that raise awareness not only for obesity, but for the stigmatisation that accompanies it.
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Tesco weigh in on obesity crisis
Tesco is axing sugary drinks that target children. This would see some of Britain’s best-selling brands, such as Ribena and Capri-Sun disappear from shelves from September 2015. This move comes after Public Health England published a report entitled ‘Carbohydrates and Health’, calling for a 20% tax on sugary drinks to help combat obesity. David Beardmore, Tesco’s soft drinks director explained that the “supermarket is removing the drinks from its shelves as part of negotiations for a range overhaul of its children’s juice category”. The ban is not across all forms of sugary drinks, the focus will be small cartons and bottles of added sugar drinks that commonly see their way into children’s lunch boxes.
In a statement, regarding the decision, Tesco said: “We want to help our customers make healthier choices and that’s why we have pledged to continue to cut sugar from the food and drink on our shelves. From September all the children’s juice drinks we sell will have no added sugar in them because we know it’ll make a positive difference to children’s health.”
Read more here and here
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Benefits of laparoscopic sleeve gastrectomy diminish with time
Five years after weight loss surgery, patients can regain the weight that they had initially lost, according to a recent Israeli study. It has long been known that surgery remains an effective treatment for weight loss, however long-term follow-up data remains sparse. Whilst also seeing a gain in weight, a recurrence of diabetes was also noted. The study followed 443 who underwent sleeve gastrectomy. After the first year patients had lost 77% of their original weight, after 5 years the weight loss was only 56%. With regards to the diabetes, 51% saw it disappear in the first year, however by the fifth year only 20% of patients were diabetes-free.
The intention of a sleeve gastrectomy is to reduce the size of the stomach similar to that of a banana. Dr Andrei Keidar, one of the researchers, explains that several reasons could contribute to the fact that weight is regained. “The main reason is that the stomach dilates, meaning you can eat more. The appetite also comes back so patients want to eat more.” Furthermore, he described how the effectiveness of weight loss surgery has a behavioural aspect and “if you don’t change your behaviour, you are going to regain weight”. A large limitation of the study was that many patients dropped out at each stage but the follow-up rates in this study correlate with similar studies of its kind.
The benefits of this weight loss surgery are still relevant as meaningful health changes are seen with just 5% weight loss, so having lost 50% after five years is still going to vastly improve one’s health. More worrying however is the re-occurrence in diabetes.
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Exercise-mimic molecule may help treat diabetes and obesity
A new molecule that acts as an exercise mimicker could potentially treat type 2 diabetes and obesity, according to scientists from the University of Southampton.
The new molecule, compound 14, was developed by Professor Ali Tavassoli. The molecule blocks the function of the cellular enzyme ATIC, which holds an important role in metabolism. The blocking of ATIC leads to an accumulation of a molecule called ZMP (5-aminoimidazole-4-carboxamide ribonucleotide) in cells, activating the cells’ main energy sensor, an enzyme called AMP-activated protein kinase (AMPK) that monitors and responds to changes in the intracellular AMP/ATP ratio. Activation of AMPK causes the cells to believe that they are low in energy, which forces the cells to increase energy levels by boosting the metabolism and increasing the uptake of glucose from the blood stream.
The study, recently published in Chemistry and Biology, tested compound 14 on a mouse model of metabolic syndrome to show therapeutic viability.
“The issue is that established drugs do not successfully enable patients with type 2 diabetes to achieve glycaemic control and some can even result in weight gain, a leading factor driving the diabetes epidemic. In contrast, this new molecule seems to reduce glucose levels and at the same time decrease body weight, but only if the subject is obese,” says co-author Dr. Felino Cagampang.
This study still warrants further research to determine how compound 14 works on treating type 2 diabetes and obesity in mice, and if this can be applied to humans, particularly if there are fewer side effects.
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Weight loss – a futile exercise?
This is a conclusion from a large UK-based study conducted over 10 years. The analysis covered nearly 300,000 adults with data taken from the UK Clinical Practice Research Database, which is an anonymised database of longitudinal patient electronic medical records. Being the world’s largest primary care database and containing more than 7% of the UK population, the data is thought to be largely representative of the UK.
The study found that the chance of returning to a normal weight whilst being obese was 1 in 210 for men and 1 in 124 for women over a year. In morbidly obese patients these figures were 6 times worse in each group. Additionally, the research found that the probability of obese patients with BMI 30-34.9 (simple obesity) achieving a 5% weight reduction were 1 in 12 for men and 1 in 10 for women, however most had regained this weight and more after 5 years.
The study raised questions against the efficacy of current obesity treatments, saying that ‘current nonsurgical obesity treatments are failing’. It called for research to develop new and much more effective approaches to obesity management programmes that stop further weight gain and maintain weight loss. One of the authors of the paper, Professor Martin Gulliford commented that ‘the greatest opportunity for stemming the current obesity epidemic is in wider-reaching public health policies to prevent obesity in the population’.
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