Continuing the theme of lifestyle influences on health and misinformation, I saw a patient in clinic last week who had taken the advice to join a gym and exercised regularly for 30 minutes 3-4 times a week. They were bitterly disappointed that they had not lost weight. In a similar vein, I was teaching medical students about hypertension a few weeks ago and they very reassuringly offered lifestyle intervention as the first treatment option for many patients. We explored this a little further, and they compiled a list of advice that they would give. My question to them was how a patient would respond, how I would respond, if they had this list put in front of them? We agreed ‘run away and never come back’ would probably be the answer as the whole package was just overwhelming and unrealistic. So getting to the point of this blog, education with the real facts and achievable goals must be the aim. Government and health care professionals are, I would suggest, guilty of often getting this wrong. Diabetes is perhaps the area where this is most often seen. It is fascinating to look at the targets for glycemic control proposed by the American Diabetes Association. A drive for physiological control has been replaced by a recognition that one size does not fit all, with more realistic targets now being advocated for many people. Fortunately, this real world approach has been supported by evidence of harm caused by targets that are too low in some groups.
So what are the benefits of exercise? I always start conversations about exercise by emphasising that there are many benefits other than weight loss. I think this is essential as these benefits will not produce any tangible change, no positive feedback, and so are less strong drivers. What people want to achieve is weight loss, and this is more difficult. The patient I was talking to recognised that the cycling that they did as part of their 30-minute exercise stint only burned 10 calories. So they had some of the information they needed. This exercise session probably only burned 100 calories in total. Very well worthwhile doing for a whole host of reasons. A fact I often use is that trained athletes have almost undetectable resting blood insulin levels because the whole system of glucose homeostasis works so well, thanks to their exercise regimen, that only low levels of insulin need to be produced. Now we cannot all exercise to this level, but the point is made. So there are benefits; but not calorie burning for the amounts of exercise that many of us can do. I row regularly on a Concept2 rowing machine. As with my patient’s bike in the gym, it estimates calorie burn. If I row for 30 minutes, I burn about 450 calories. However, if I then drink a 250ml glass of my favourite smoothie (must be good!) 150 calories are replaced instantly. In contrast, the same amount of no added sugar cranberry juice is only 10 calories. Now I am not saying the smoothie is not good. But knowledge is everything. Awareness of the calorie content of what we eat and drink is essential. Packaging is much better, but I still sometimes struggle to work out calorie contents.
There is also the concern that if people exercise to higher levels and significantly gain muscle mass they will of course gain weight as muscle is denser than fat. But this is not a serious concern for most people I have this conversation with.
And of course exercise also tends to increase appetite.
So the advice that I give is that exercise is fantastic, but to achieve weight loss it has to be coupled with calorie restriction. I suggest that if all of us look honestly at our daily diet we will find some calorie rich foods or drinks. Reducing, stopping, or swapping these things for lower calorie alternatives, will produce the biggest benefit. But, I also emphasise that it will take time. Another fact comes to mind, it’s a bit of a knight’s move, but I think is relevant. This was shared with me by a professor of diabetes who taught me an enormous amount of practical, real world, common sense medicine. The fact relates to populations that gain weight through adult life as opposed to populations that maintain a healthy weight. What is interesting to me is that the difference in daily calorie intake between these populations is small: about 50 calories. So for me the point is that it is not about crash diets, but making small real sustainable changes to our daily calorie intake and then being patient. Over the weeks and months our weight will come down as a result of making these changes.
I also refer many people to dietitians for professional advice. But, I hope my real world thoughts help push people in the right direction.
And then picking up on my theme of representation of these things in the media, I watched a very interesting programme recently. It looked at intra-abdominal fat content emphasising that this fat is particularly bad for us. The programme also flagged up the fact that we can have significant amounts of intra-abdominal fat without being obese. Finally, it suggested that complex carbohydrate as found in lentils could reduce intra-abdominal fat, whilst recognising that this needed you to eat LOTS to actually achieve this. So impressive reality rather than sensationalism. Finally, the programme suggested that inulin powder addition to foods was an alternative. Sounds interesting so I thought I’d dig a bit deeper. Avoiding promotional sites, Health Benefits of Inulin seemed to provide a balanced view. The diabetes study referenced therein is a good study. I’m not so sure about the other references, but overall I think this is a good overview. The relevance of abdominal fat is outlined in a number of sites e.g. Abdominal fat and what to do about it), although I’m not sure I entirely agree with the exercise advice as above. In animals, inulin supplementation clearly reduces intra-abdominal fat (Dietary long-chain inulin reduces abdominal fat but has no effect on bone density in growing female rats) and these benefits seem to translate to man (A randomized controlled trial: the effect of inulin on weight management and ectopic fat in subjects with prediabetes). The problem of course is that some companies have jumped on the bandwagon, and some inulin is expensive. A typical dose used in the studies cited above is 30g/day. With care this can be found at a reasonable cost. Of course, increasing intake of foods rich in fermentable carbohydrates such as inulin is the best way to achieve this.
So correct, realistic, achievable advice has to be the way forward to achieve lifestyle
modification for both ourselves and our patients!
Dr. Richard M. Smith, FRCP, PhD
Guest Post Writer
Dr. Smith studied medicine at Cambridge and Oxford and completed his PhD at Cambridge University. He worked as a Consultant Senior Lecturer in Nephrology in Bristol, where he led a research group continuing his interest in the immunology of transplantation and factors determining pancreas transplant survival, and was actively involved in clinical trials. He continues to teach postgraduate students on the Cardiff University Masters course in Diabetes.