Hunter Gathering in the press

My first blog post after an extended absence – a wedding, honeymoon and revision for impending medical school exams have left me little time to contribute here.  I shall try and be a little more frequent over the next few months!

Writing in today’s New York Times Sunday Review, Herman Pontzer highlights the fact the our last remaining hunter gatherers, in this instance the Hadza of Tanzania, don’t remain free of the scourge of obesity by virtue of greater energy expenditure.  The article summarises the full publication in July’s edition of PLOS One.

In essence, a team tracked the activity levels of a small number of Hadza men and women as they went about their daily lives.  The conclusions were fairly straightforward:

  • Hadza men and women aren’t any more ‘efficient’ in their physical activities, nor do they compensate for raised activity levels with changes to their metabolic rate
  • Activity levels in the Hadza were not significantly different to Western societies
  • Their % body fat was lower than western populations
  • There was no correspondence between % body fat (adiposity), activity levels and daily energy expenditure

So perhaps the constant protestations from the popular press for us to stop frittering our lives away in front of The X Factor, to jump onto a treadmill and mindlessly grind-out two and a half hours of aerobic activity each and every week until we’re 64 are all a waste?

Worse still, our obsession with always being in an ‘aerobic zone’ whilst we conduct our physical activity misses the point to be learnt from our svelte Tanzanian cousins.  They walk miles each day (mean values of nearly 6km for women, 11km for men), the women carrying heavy loads of fuel and water, the men hunting game and collecting honey. In other words, their typical activity levels fall either side of the aerobic zone: they burn adipose fat happily all day by not depleting their glycogen reserves with extended bouts of aerobic work.  They also drag game, climb trees and dig up tubers: short duration work, more likely to rely upon the immediate energy (ATP) stored in the muscles or anerobic breakdown of gylcogen over a short period of time.   Perhaps it is this mix of polar opposite exercise types that, although not reflected in the dry statistics of daily energy expenditure, has a critical role to play?  I’ve blogged before about the myriad positive hormonal effects of short duration intense activity.

Maybe the answer lies in their energy consumption (or put another way, what they don’t eat)?

  • A lack of processed food
  • No reliance on grains
  • No seed oils

As an afterburner, for all those fretting over macronutrient ratios, note that the Hadza must consume some carbohydrate with all those tubers!

Enjoy the weekend!

Food for thought…

Heavy Squats and Pulled Pork: a guide to manipulating myostatin, testosterone, leptin and growth hormone. Part 2

This article in the European Journal of Nutrition indicates that undue fuss over exact pre and post workout feeding regimes and macro-nutrient ratios might be all for nothing.  A group of 10 ‘untrained’ college men participated in a study where they conducted three resistance training sessions: 3×10 reps (80% of 1 rep max – although how you work that out in an untrained athlete is interesting) for hack squat, leg press and leg extension.  2 hours prior, and 6 hours post exercise, muscle biopsies were taken and analysed for mRNA fold-changes in myostatin.  None of the feeding regimes appeared to affect the expression of myostatin.  However, biopsies post training showed significant  reduction in myostatin expression (p <0.05).

Does this have significance for those who already train regularly?  Would the same down regulation appear with training below 80% of 1 rep max?

Food for thought…

Standby for my next post, which will be on acid/base balance, and the role of dietary electrolytes and macronutrients in maintaining this balance (in particular, the role of acid load on bone demineralisation).