Monthly Archives: February 2018

The behaviour of fat and the impact on how easily obese people can lose weight

Dr Katarina Kos leads the adipose tissue biology group at the University of Exeter and researches obesity-related disorders.

Obesity is one of society’s most pressing concerns. Suggestions for diets and weight-loss regimes are on everyone’s news feed.

The role of psychology and human behaviour is recognised as a key factor for success, but little appreciation is given to the behaviour of fat itself.

This is something that my research at the University of Exeter has begun to address. Studies have found that the way fat behaves can have an impact on how easily obese people can lose weight.

In my role as a clinician working with people who are struggling to lose weight, I know how hard losing those extra pounds can be.

That is why I hope my research into the behaviour of fat will with time offer solutions to help make this easier.  In the first stage of a longer research project, we have identified the type of damage done to fat tissue when overworked and are now studying in more detail which molecules are involved.  Next we plan to explore which drugs might help people to reverse the damage.

The most recent study, Lysyl oxidase and adipose tissue dysfunction looked at a molecule which is impaired when fat is struggling and overloaded with excess calories.

Like human beings, overworked fat ‘complains’ and becomes distressed and struggles to do its job. As fat cells begin to struggle for oxygen and suffocate under the burden of storing more and more energy, the fat becomes inflamed and as a result scarred.

The research by the Exeter Adipose Tissue biology group that I lead examined the molecule LOX in fat tissue which causes this scarring. The paper, drew a good deal of media interest both in the UK and around the world.

Scarred fat tissue is fibrous and rigid and less able to store excess energy. To compensate, the body can drive this energy to other parts of the body including the muscle (see below) and vital organs, such as the liver and heart, which it can cause serious health complications.


Above, a picture of bacon where we find fat in the muscle described as mottling.

The study showed that fat scarring may not resolve itself with weight loss. In fact, there is evidence that the more the fat tissue is scarred, the more difficult it can be to lose weight in the longer term.

But this does not mean that people who are obese should lose hope. Not all obese people have scarred fat and even those with scarred fat can shift excess pounds.

In my clinical work, I talk to obese people all the time have tried for years to shift those extra pounds, and, based on my experience, I can offer the following advice.

  • Almost everyone can lose weight. Most heavier people succeed in losing some weight, but many put it on again, some very quickly. Our previous research has shown that women with weight problems have managed to drop dress sizes on many occasions and that Yo-yo dieting, and weight regain after weight loss is very common.Research suggests that it may be more difficult for obese people with more scarring of their fat to be as successful with weight loss as those with less scarring. With established scarring and exposure to excess energy, these calories are increasingly stored in unhealthy places, including on the tummy and within vital organs. This can predispose people to health problems including diabetes, fatty liver, high blood pressure and heart disease. However, even people with scarring can lose weight, though not necessarily quite as much and most would not expect and want to become a size 0.
  • A person does not need to be clinically obese to have scarred fat tissue. We do not yet understand why some people are more prone to fat tissue scarring than others. Some may have a genetic predisposition similar to the increased risk of diabetes.  We find fat scarring in people with a more extreme but rare condition called lipodystrophy where people have very thin arms, buttocks and legs and a disproportionally large tummy. It could also be that certain foods make us more prone to fat scarring regardless of the amount of energy they contain.  We are embarking on further research to learn more about this.
  • Help your fat tissue by using muscle to cope with excess calories.  Even just a short walk after a meal helps. Any type of calorie, whether from a diet of surplus fat, sugar or protein can be stored as energy in fat tissue once the body has met its energy need. But with a growing amount of fat tissue, it struggles to take up blood sugar into the fat cells and requires more and more insulin to do so. This is known as insulin resistance which can progress to pre- diabetes.  Once the pancreas fails to supply sufficient amounts of insulin and the pancreas is overworked, this can progresses to diabetes Type 2. We are studying when best to use activity breaks in sedentary people to help unburden the fat tissue.  Preliminary research by my team now being pursued has found that a short walk after a meal can have a beneficial effect on lowering blood sugar.
  • Why eating the same amount of calories will not mean you will be of the same weight. Some people seem to eat a lot but never gain weight, while others appear to eat like birds and struggle.  Whether the calories are in excess depends among other things on our metabolism, our age and whether we are fidgety, sedentary or active. There are also big differences in energy needs between men and women. Generally, women require far fewer calories day to day.
  • A lot of the ‘Obesity damage’ can be reversed through weight loss.  Many obesity-related health problems are reversible, especially if their onset is of more recent duration. Studies have shown that even modest weight loss (5% of total body weight) can reduce blood pressure, cholesterol, blood sugar and with it also the risk of heart disease.  Fat tissue recovers from inflammation and fatty liver disease can also resolve. Recent studies show also that diabetes can improve or vanish with weight loss. The same type of operations used for weight loss surgery can also be very effective in managing Type 2 diabetes and are thus also called ‘metabolic surgery’.

So what should you do to keep fat happy and allow it not to be overworked?

My tips, based on my experience working with patients with weight problems, are:

  • For those who struggle with their weight, do not despair. Weight loss is possible.  Even for those whose fat tissue is scarred, you may not reach a size zero, but with determination and lifestyle change you can shift those pounds, but it will take commitment. In my experience, people, with the right commitment, manage to lose 5 per cent of their body weight or a stone in six months which is a realistic target.
  • Weight loss will be more easily sustained without the use of radical calorie restrictions, but with changes to well- rehearsed habits.  You can cut your calorie intake by 400-500 calories a day by eating from smaller plates, avoiding refined sugars and junk food and start eating more slowly.  You do not need to give up snacking altogether. Trade crisps and cakes with healthy options such as chopped vegetables and yoghurts, swap ice cream for sorbet and think twice about cream.  Consider also whether you are consuming many liquid calories from alcoholic and non-alcoholic drinks, as they also count.
  • Do not cut too many of your calories at once. It is the little changes that will become a new, healthy habit.  This is not about being on a diet for a period of time, it is rather about adjusting your lifestyle for a lifetime. This will require commitment and may not always be comfortable. People who find a buddy to join the efforts are more likely to be successful.
  • If your doctor has tested you for obesity- related health complications, or you have been told you have fatty liver disease or diabetes and have a much larger waist than hip circumference, weight loss can make a great difference to your health and turning your life around will make you a healthier person.
  • For those of average weight  – you are not immune from unhealthy fat.  One possible sign of this is if your waist is wider in circumference than your hips.  You may want to follow the advice above.  Regular activity will help you to a healthier body and better fat proportions. As exercise drives oxygen to all your tissues including the brain boosting concentration and decreasing the risk of dementia.
  • For the lucky lean ones: you may have a natural protection from disordered fat, however look at your parents and their health as this is likely to predict your future risk. We tend to increase in body weight as we age.
  • For anyone: avoid big meals to absolute fullness and always consider some light activity e.g. a walk after consuming large amounts of calories.
  • Have breakfast and do not teach your body to go into starvation mode as this will make it more energy efficient which will not help your weight. Smoking will decrease tissue oxygen levels which damages fat and causes scarring. It also increases the likelihood of wrinkles! If you sit at a desk all day, try to break up periods of sedentary work with short periods of activity – whether walking to the copy machine or up some stairs – especially after you just had a meal. Even small activity changes will help your fat tissue and stop it from becoming overworked.

Socialise with activity in mind. Loneliness and boredom does make us seek comfort in food. People who find a buddy to join weight loss efforts are more likely to be successful.  Consider options where you can socialise with sporty activities from a walking group to taking on a challenge of a run with your mates.

Being kind to yourself can help weight loss too. Stress increases the risk of overeating and comfort eating and disturbs sleep and we know that a disturbed body clock affects our weight negatively. Find calorie-free happiness instead (a bath, book, music to dance to, chat with a friend, a fun past time which could be anything from knitting to sculpting, from gardening to playing golf).  Do set yourself a realistic target. Having a target or a sporty challenge in mind with a date set will keep you focused. This could be anything from a 5km walk to running a marathon, from climbing the local hill to a mountain, from swimming a length in the pool to crossing the English channel.  And for those with mobility problems sitting exercises, including yoga, may be an alternative. Many people opt for swimming as it is gentler on the joints.

Do not judge yourself on the way you look or your body weight, leanness does not bring happiness. However, people with weight problems are more frequently depressed. Seek treatment which maybe in form of talking therapies or tablets as this will help you to be stronger and to take on the effort and commitment to look after your weight.

Be forgiving to yourself as setbacks are natural, life happens and distractions occur, allow them to pass and get back on track. You can do it!

Here at Exeter we are at the forefront of research into obesity. Our research is optimistic. We are looking into whether the timing of activity can aid weight loss, which types of foods predispose us to fat tissue scarring and which drugs could help improve scarred fat tissue. We are also looking at genes which are linked to healthy and unhealthy fat.

We think obesity is something that can be tackled. But we need the best science to help people fight that unhealthy fat and keep unwanted pounds off. That way we can help tackle diseases such as diabetes, heart disease and strokes. Let’s get moving.

By Dr Katarina Kos, Senior Lecturer at the University of Exeter’s Medical School