Monthly Archives: June 2018

Reflections on Parliamentary Links Day 2018

By Charlotte Haigh, University of Leeds, @LottieHaigh

I was very honoured to be invited to Parliamentary Links Day, by The Physiological Society on the 26th June. The theme this year was science and the industrial strategy. Being Yorkshire, born and bred and still living up north, you don’t often get these opportunities and I was very unsure what to expect.

After arriving early and going through security checks, I found myself in a packed room in Portcullis House ready for the start of the day. Although the event was organised by the Royal Society of Biology, 13 other societies were represented by banners at the event from across the breadth of science, technology, engineering and maths.

The morning session was filled with speakers including five MP’s, the Government Chief Scientific Advisor and a representative from UKRI. These speakers all pulled out key points of how the science and industrial strategy is aimed to be delivered and how increasing the funding of R&D in the UK wasn’t the only challenge. The speeches were broken up by two discussion panels of people from many of the represented societies talking about how they were contributing to influencing and delivering some of the key elements of the strategy.

It was made apparent at the start that not many MP’s are well-versed in science, and this is a problem. We need more scientists and engineers in the House of Commons. This surprised me at first but then on reflection, as scientists, not many of us would aim for that type of profession.

The Chair of the Science and Technology Select Committee, Norman Lamb MP, highlighted how important it is that we continue to get the best people to work in science in the UK. Government is currently working on a blueprint of the pact we need to agree on for science in the Brexit negotiations. I am sure many of us would support this.

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Dr Patrick Vallance, The Chief Scientific Advisor, speaking 

Many of the discussions we have been having in the higher education sector at present and for many years were highlighted and discussed. We need to nurture young talent from an early age, right from primary school. We must concentrate on achieving diversity in areas such as gender and ethnicity in all STEM areas, taking it seriously and not just paying lip service to it. We should value technical staff and give them opportunities to flourish. There was also a discussion raised by our own Andrew Mackenzie (Head of Policy and Communications) about the issue of 45% of public spend on R&D going to the golden triangle (Oxford/Cambridge/London) and how we need to focus on getting economic development to poorer regions of country.

So what are my reflections on this day? Well, it was interesting to hear all this and there were no surprises in what was said. Lots of challenges, but not many answers. Many of the discussion points raised resonate and are mentioned within The Physiological Society’s new 2018-2022 strategy which is great to see. Throughout the day, lifelong health (The Society’s policy focus) was mentioned, more than once, as one of the grand challenges for STEM going forward. I think being involved in a day like this is important for The Society and its members, to make the government aware who we are and what we do and promote what I hope is a two-way stream of communication between Government and the scientific community. It was great to hear that ‘scientists on the coal face must be supported’ but the cynic in me questions how the government can really achieve this.

If you wish to see anymore highlights of the event, visit the Royal Society of Biology Facebook page or search #LinksDay18 on Twitter.

 

 

Why dieting is bad for you

By Simon Cork, Neurophysiologist, Imperial College London, @SimonCorkPhD

According to a 2016 survey of 2000 people in the UK, almost two thirds of us are on a diet at any one time. For most people, the typical diet consists of eating a salad for lunch, and cutting out desserts and snacks. NHS guidelines for weight loss recommend reducing calorie intake by around 600 calories each day. But is this advice right?

There is a theory among many scientists in the obesity field that body weight is fixed around a “set point”. That means that for the majority of people, body weight is typically static (unless drastic changes are made to exercise or diet). Any fluctuations in our body weight are compensated for by either increasing or decreasing energy input or output. You might feel this if you’re on a low calorie diet by feeling constantly tired and feeling like you just want to sit down. That’s your body’s way of trying to conserve energy.

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One method our body uses to keep its weight constant is a hormone called leptin, released by fat cells into our bloodstream. The more fat we have, the more leptin we have flowing through our blood. Normally, leptin acts in the brain to restrict appetite, effectively acting as the brake to restrict major changes in body weight. Minor increases in fat lead to increases in leptin, which reduces appetite. Loss of body fat causes decreases in leptin and thus increases in appetite to compensate. Leptin is therefore the body’s messenger to the brain, informing it of our weight.

The problem occurs when we override the effects of leptin, typically with respect to its appetite-restricting effects. More fat means more leptin, which should reduce our appetite, and thus reduce our body weight back to what our brains perceive as “normal”. However, if we override these effects (e.g. by ordering dessert after starters and a main, or eating large portions, thus eating past the point of feeling full), our brains eventually become resistant to leptin.

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Leptin levels are directly correlated with body weight. Bronsky et al, 2007.

This leptin resistance effectively means that our brains are tricked into underestimating what our body weight truly is. Although a 150 kg person has more circulating leptin than a 70 kg person, the extra leptin doesn’t decrease appetite as it should because the brain has become resistant to leptin: it needs more leptin to have the same effect. The brain is therefore “tricked” into thinking the body has less fat than it really does.

This has significant consequences when people who want to lose weight go on low calorie diets. As we restrict food intake, we lose body fat. For reasons not fully understood, the levels of leptin fall at a greater rate than body fat. Our brains react by activating mechanisms to restrict any further loss of body fat and promote energy storage. One such reaction is lowering the resting metabolic rate – effectively the minimum amount of energy required to keep us alive.

You may remember a US TV series called “The Biggest Loser”. This show took overweight or obese people and subjected them to a gruelling exercise and diet regime. The contestant who lost the most weight by the end of the show won a significant cash prize. In 2016, the results of a study were released which followed the contestants after they finished the show. They found that almost all contestants regained their weight and found that some regained more weight than before they started.

And this is the crux of the matter. It has been found that people who go on crash diets significantly reduce their resting metabolic rate – effectively, they are using less energy just by being alive than before the diet. And this metabolic rate may never recover – even after stopping the diet.

This may explain why a number of contestants regained more weight after the show than they started with. Their bodies are constantly fighting against a famine. It may also be why most people who go on a diet fail to maintain their low body weight long term. This is the key issue that many people developing weight loss therapeutics are facing.

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Calorie restriction (CR – blue line) results in significant decreases in resting metabolic rate (RMR) Davoodi et al, 2014

For many people, losing weight is relatively easy. Simply restricting calories and/or increasing the amount of energy we use, usually by exercising, will result in weight loss. Maintaining that weight loss is the key issue. Exercise is often the key to maintaining weight loss, but is difficult to maintain the necessary levels of exercise required to compensate for the decreases in energy use that occurs following dieting.

Scientists are currently investigating how to manipulate the body weight set point, by both re-sensitising the body to leptin (i.e. countering the leptin resistance), and/or by increasing the levels of naturally occurring hunger-suppressing hormones that our bodies release after eating.

If decades of dieting advice has told us anything, it’s that dieting doesn’t work to bring about long-term weight loss. But importantly, by permanently reducing the resting metabolic rate, dieting may actually be preventing our bodies ability to lose weight in the future.