Let us start with the premise that a fat, inactive group of people has poorer wellbeing than a thin, active one and it is desirable to try and move people from the former to the latter. Prevention of chronic disease and improving resilience of the population should reduce pressure on overstretched health service worldwide. Diabetes is a classic example, with NICE continuing to recommend a diet consisting of 50% carbohydrates for a disease caused by insulin resistance! It seems illogical not to have carbohydrate restriction as first line management for diabetes.
We also need to clear the confusion around inactivity and obesity. Firstly, becoming active will not make you become thin. More activity makes you hungrier and if you diet you become more sedentary. To state that obesity is merely a function of calories in and calories out is unhelpful when trying to bring about behaviour change in a species that has evolved to deal with under supply of calories. The problem is not obesity per se, but fat storage. The human race has genetically evolved to store fat. If you were someone who could store fat efficiently, then you would survive wars, famines, droughts, and plagues, and pass those genes on to the next generation. In the last 60 years or so the food industry has worked out how to produce loads of carbohydrate rich foods at immense profit. We still store fat very efficiently so this has created the obesity epidemic. One of the reasons that NICE still recommends a high carbohydrate diet is that fats in particular are energy dense foodstuffs, but this also presumes rather illogically that humans will consume the same weight of food irrespective of calories!
The food industry is cunning, however, and is now trying to blame simple sugars solely for this problem so diet drinks are now literally becoming the flavour of the month. The problem is that all carbohydrates are problematic, even the so called ‘healthy stuff’, such as potatoes, rice, bread, pasta, etc. Carbohydrates are the only component of food to stimulate an insulin response leading to conversion to free fatty acids and then triglycerides – within 2-3 hours the individual is hungry again. Having one of the most sedentary populations in the world and our grazing culture creates the perfect storm.
I should say at this point that we are a divided country and if you are active in the first place then it probably doesn’t matter very much what you eat as you merely use it as fuel.
There is also the commonly held belief that fat consumption clogs up your arteries, but several studies, including meta-analyses, have consistently failed to show reduction in levels of heart disease with low fat diets.
Finally just to really push the boat out one should question the mantra of five (fruit and vegetables) a day. Although studies have shown some reduction in cardiovascular disease, there is little evidence for the reduction of rates of cancer. My suspicion for the mixed message is that fruit and vegetables are not the same. Five 100g portions of random fruits will give you around 380 calories. Five 100g portions of vegetables will give you around 80 calories. So not only an insulin response and fat storage with fruit, but also an extra 300 calories.
Many people engage with activity to lose weight and disengage because their primary motive is not achieved. Inactivity has been shown to be the single worst thing you can do to yourself. A massive study of 364,000 patients over 12 years published earlier this year showed it is twice as likely to kill you as obesity.
So the bottom line is get active but be aware that is so much easier to do that if you are thin. To do that, get rid of the carbs!
— Dr Ewan Hamnett, Birmingham’s Champion for Physical Activity, Board Member UK Active
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