The ups and downs of a high protein diet.

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If we want to get stronger we  need to eat plenty of protein.  The easiest weight loss diet to follow is high protein/low carb – its the most satisfying.  Follow it well and we don’t feel hungry, have to count calories or microscopically examine everything on our plate.  I do have two worries about people just jumping into this way of eating.  And, of course, there has just been another study published vilifying the eating of dead things: bird, beast or fish.

This new study shows that under the age of 65, a high animal protein diet is associated with a higher risk of developing cancer.  Over the age of 65, its surf and turf all the way. 1  Under 65 its presumably beans and tofu since the study stresses the importance of getting protein from vegetable sources.

The principal author, Valter Longo, attributes his findings to high levels of IGF -1 in the blood of those of us who eat animal proteins.  IGF – 1 is short for Insulin Like Growth Factor.  IGF-1 is anabolic, meaning it builds muscles up.

6,381 people took part, aged 50 and older, with the average age of 65.  The data used for the study was collected from the long running American survey of health, NHANES lll and is based on a single twenty four hour dietary recall of each participant.  The mortality rates of the participants were then monitored for the following 18 years.

Studies of populations around the world who are healthy and live long lives often show they have a lower intake of meat.  The particular population that has interested Valter Longo live in South Ecuador and have a unique genetic defect that means they do not make IGF-1 in their blood, and so are largely immune to cancer and diabetes.  This defect is called Laron syndrome.

Its not all good news for them though – they are very short, well under four feet tall, tend to be obese and the men have small penises.  These people do not live long lives because they drink heavily.  Nevertheless, Longo uses them as a prime source of his discovery that IGF-1 is the demon in causing cancer.

People like the Okinawans are often held out as being super healthy.  If we look at them, it is their whole way of life that is very different.  Apart from anything else, culturally, they eat until they are about three quarters full and never stuff themselves or skip meals.  They eat plenty of fermented foods including the soy – not for them soya milk or Tofu.  I also think that the lifestyle of the average 65 year old American, or Brit, come to that,  bears little resemblance to that of the average 65 year old Okinawan.

What troubles me most about this study is the age group.  For the average American – or Brit – when climbing over 50 years old,  the amount of exercise done tanks.  By now, exercising tends to hurt, we no longer bounce back as we did in our twenties.

When I train someone and they want to get stronger, putting them on a high protein diet is vital – they need IGF-1 in their blood to make their muscles grow.  We are using the IGF-1, not having it sloshing about our lazy bods.

So maybe the study is right – people happy to embrace warm slippers and leisure time spent snoozing in front of the TV should restrict their protein intake.   For them, replacing steak and salad with a pizza must be the way to go.  Has to be healthier.  The little people prove it.

My reservations about the high protein, low carb diet: absorption and sprouts.

I have never come across anyone who passes the HCl test.  Not enough HCl (hydrochloric acid) in the stomach means that proteins can’t get broken down properly.  The best sources of the all important minerals, iron, zinc and magnesium are from meat.

Zinc is used by the body in the manufacture of HCl, so poor digestion of meat means poor uptake of zinc which leads to less and less HCl.  Meat that is not properly broken down in the stomach really is a problem, since it then trundles through our guts, a nice warm, bacteria rich environment, rotting gently. Women have even worse digestion than men – maybe it is because we give our precious zinc etc to our babies. 2

The other problem with a high protein diet is that it must still contain plenty of vegetables.   Meat and cheese are acid forming, vegetables and fruit alkaline.  Ideally we are slightly alkaline,  so eating a whole pile of vegetables along with our shank of lamb will counteract the acidity of the meat.  Vegetables are also good sources of antioxidants, vitamins and fibre.  Incidentally, exercise makes us much more acidic than any lump of parmesan cheese can.  So if we do exercise, we really need our veggies.

Some lucky people have a gene that makes bitter foods taste nice, so they nosh down the radicchio with joy.  This gene also means that their guts extract nutrients more efficiently.

Therefore, its all very well to counsel greens eating, but it gets difficult when greens taste horrible.  That said, when we want to, we can aquire a taste for a food: most vividly remember that first drink of beer and how horrible it tasted, so in my day, we drank lager and lime to develop a liking for beer.  Blarggggh…..

Good aging is associated with good muscle mass.  Maybe why this study showed that eating more protein after the age of 65 is beneficial. 3 4

The fact remains that meat based protein is the only source of vitamin B12, it is the best source of minerals, it is the best source of carnitine, vital for brain health and it is the only source of IGF-1.  We must be able to fully break down the meat and we need to counterbalance it with plenty of vegetables.  It may also be that we need to shove heavy stuff about regularly to put that IGF-1 to good use.  Before embarking on this, though, do take care when picking a personal trainer……


  1. Low protein intake is assicated with a major reduction in EGF-1 cancer, and overall mortality in the 65 and younger but not older population.  Levine ME, Longo VD.  Cell Metabolism, Vol 18, issue 3, 407-417.  4 March 2014. []
  2. Incidentally, zinc is also important in the manufacture of testosterone and in the immune system.  Low zinc, low testosterone and loads of colds.  Does low testosterone matter for women?  Oh yes.  The female version of testosterone gives us a zest for life. []
  3. In the study, Longo does hypothesise why eating meat over 65 is beneficial, and one reason he touts is actually to do with absorption in the gut, which, as he acknowledges, gets worse with age. []
  4. However, resistance work – shoving heavy stuff about – is fraught with muscle pulling danger.  The most enormous majority of people , particularly over the age of about 30, are in no fit shape to take up serious bench pressing, for example. Many runners fight shy of leg strengthening because their legs feel much worse after doing a few heavy squats and lunges – they are correct, they are worse.  At fault is their alignment and eventually they will have to give up running and start cycling, or, even worse, take up spinning classes. []

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