Naked Science Forum
Life Sciences => Physiology & Medicine => Topic started by: John Chapman on 06/02/2009 16:12:24
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My question is in two parts:
a) I am fortunate enough to be able to eat voraciously without putting on weight. And I do! My brother, on the other hand, is constantly battling with his weight despite the fact that he eats considerably less than me, probably more healthily and works out at the gym. He says his weight problem is just 'his slow metabolism' but what is the real reason he puts weight on more easily? If my metabolism really is running faster does this mean I am aging more quickly than him. In other words is his 'engine' gently idling whereas mine is constantly revving and hence wearing out faster? When it comes to metabolism, does the flame that burns brightest burn quickest?
b) I also eat an awful lot of sweets, crisps and cakes. But my appetite is large enough that I also get to eat quite a bit of fresh fruit and veg. Also my cholesterol level is low. Is there any reason why I shouldn't eat lots of unhealthy snacks if I also eat my five a day?
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There appears to be a lot of conflicting information about metabolism and life span on the internet.
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One of the aging theory says that the faster an animal's metabolism, the shorter its life and vice versa.
Thyroid Hormones Linked to Aging (http://news.softpedia.com/news/Thyroid-Hormones-Linked-to-Aging-37607.shtml)
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Uncoupled and surviving: individual mice with high metabolism have greater mitochondrial uncoupling and live longer.
http://www.ncbi.nlm.nih.gov/pubmed/15153176?ordinalpos=1&itool=EntrezSystem2.PEntrez.Pubmed.Pubmed_ResultsPanel.Pubmed_DefaultReportPanel.Pubmed_RVDocSum
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I also eat an awful lot of sweets, crisps and cakes. But my appetite is large enough that I also get to eat quite a bit of fresh fruit and veg. Also my cholesterol level is low. Is there any reason why I shouldn't eat lots of unhealthy snacks if I also eat my five a day?
What about your body sugar levels, blood pressure, Body Mass Index (BMI)? You can calculate your BMI here (http://www.bbc.co.uk/health/healthy_living/your_weight/bmiimperial_index.shtml)
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Dr Roy Walford of UCLA famously worked on the effects of Calorie Restriction (CR) on aging and lifespan and earned worldwide fame and a huge following. If you google either his name or the phrase 'calorie restriction' there is stacks of information to be found. He worked mainly with mice and found that by restricting their calories to about 60% of normal, while also increasing the nutritional value of their food mice greatly slowed down aging and also the contraction of diseases associated with aging, such as diabetes, thrombosis and cancers.
I once saw him on TV showing off two mice. One was tatty, had a spiky unkempt coat, moved slowly and wobbled as it walked. It looked like a very old, doddery mouse. The other was sleek with shiny fur. It moved quickly darting from here to there and seemed vibrant and alert. It looked very much younger. Actually they were brothers from the same brood and, therefore the same age. One had been kept on a calorie restricted diet while the other was free to eat at will. The film was quite dramatic.
Work has also been done on nematode worms which lived on average a little over twice as long on a CR diet.
I heard last year that about 10 years previously an experiment was set up using colobus monkeys. This was being conducted by the universities of Wisconsin and Maryland both in conjunction with the National Institute on Aging. Basically they had two colonies of free-range monkeys kept in conditions as similar as possible, except that one colony had a CR diet. After 10 years it was still too early to draw definite conclusions about longevity but early indications were encouraging. Apparently incidents of age-related diseases was significantly lower in the CR colony.
Incidentally, Dr Walford was asked in an interview in an American science magazine whether the same effects could be gained by eating more calories but using exercise to burn them away. he answered:
"No. Experiments in animals indicate it does not work. Exercise does three things that at least on the surface would seem are contradictory to longevity: it raises metabolic rate, and creates free radicals"
For humans he recommends a highly nutritional diet of about 1,800 calories. He famously stated that he expected to live to 140. Unfortunately he died a year or two ago aged 79 from Lou Gehrig's Disease!
There is a Calorie Restriction Society which continues his work and extols the virtues of a CR diet. It website can be found at
http://www.calorierestriction.org/Home
I'm afraid I don't know what biochemical mechanisms are involved.