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

Today I want to describe how a few simple tweaks to your diet and training program can reap serious rewards:  I’ll be looking at the concepts of intermittent fasting, overfeeding and resistance training, and the positive effects these have on your overall health.

Intermittent fasting (IF)

Too much!

There really isn’t any firm definition of what intermittent fasting is. It can be seen as merely extending your overnight fast until lunchtime, or even later, so that you end up having only a small ‘eating window’ late in the day.  This approach has been popularised in the strength training community by Ori Hofmekler’s Warrior DietIt can refer to more radical approaches, such as 24, 36 or 48 hour fast periods, in which only water, black coffee or tea are ingested.   I take the approach of a 36 hour fast, once a week, from my evening meal on Wednesday to breakfast on Friday.  During the rest of the week I eat two meals a day; lunch and an evening meal around 7pm.

It certainly helps to be keto-adapted to give this a go (i.e. you need to be consuming a diet that is reasonably low in carbohydrate, and thus not subjecting your body to constant fluctuations in blood glucose throughout the day). You will set yourself up for success by eating meals containing quality proteins and fats prior to any fast.  Otherwise, you will find yourself at the mercy of your hunger (a topic for another occasion).  As a guide, IF shouldn’t be difficult.  Hunger should not be lurking around every corner.  When you resume eating, do so in a controlled way, with a normal-sized portion of food. Simple!

Why should I try this? Well, the benefits of IF include:

  • Increased secretion of growth hormone
  • Reduced blood pressure and increased insulin sensitivity [1][2]
  • Resistance of the brain to degradation through the production of brain-derived neurotrophic factor (BDNF) [3]
  • Improved cardiovascular health [1]
  • Increased oxidation of fatty acids [2]
  • improved plasma lipid profile (triglycerides decreased in men, HDL increased in women) [2]

And so to the fun part – overfeeding and leptin!

Food should ideally have a competitive element to it, and the IF concept lends itself perfectly to this, for the flip side to IF is overfeeding.  Overfeeding  should not be confused with ‘cheat meals’.  I often save my cheat meals for an ‘overfeed’ day once a week (Saturday or Sunday usually), as I enjoy the challenge of eating as much as possible, and not letting myself be bothered too much about where those calories come from.  As a rule though, you should be aiming to eat sensibly 80-90% of the time.

The aim of overfeeding is to temporarily gain adipose tissue in order to increase leptin production.  Leptin is a hormone, secreted by adipose fat that (along with high energy substrates in the blood and raised circulating insulin levels) inhibits the release of neuropeptide Y from the hypothalamus.  Neuropeptide Y drives the sensation of hunger, so, the more adipose fat, the more leptin, the greater the degree of inhibition of the release of neuropeptide Y.  As an aside, the majority of those who are obese are not in some way leptin deficient (they should have a considerable quantity), rather they are considered to be in some way resistant to it, and its effect upon the hypothalamus is therefore negated.  Leptin signalling essentially informs the body that energy is available in adipose fat, and thus promotes the release of triglycerides in adipose fat to fuel the body – exactly what we want to happen.  However, whilst reducing caloric intake over a number of days and weeks will be met by releasing triglycerides, whether this will continue ‘easily’ as the circulating levels of leptin drop is another matter.  So overfeeding bumps up your leptin level.  The adipose fat you store will be utilised for fuel over the rest of the week (particularly on an IF day).  In graphical terms think of a steady decrease in adipose stores over say, a monthly period, with small spikes once a week to keep the overall reduction process smooth and sustained.

Hmmm.... pulled pork

My favourite overfeed days will include, if at all possible: pulled pork, chips cooked in tripe, lots and lots of BBQ brisket and clotted cream!

As an important note, it’s worth considering the effect of fasting on your ability to train effectively.  This is very much a personal issue, but I have never had an issue with energy levels when I train on fasting days.

Resistance training

There is a lot of controversy over exactly which resistance training regime one should follow, and it varies with experience, age, goals, degree of dedication, time and equipment available etc…  but as a simple rule, EVERYONE should perform some form of resistance training.  As inactivity or age creep up on us, our skeletal muscle is slowly, imperceptibly, depleted (a process known as sarcopenia).  This is caused usually by the consumption of supposedly healthy low protein diets, high levels of cortisol from chronic, unresolved stress and reduced circulating testosterone.  There are two key issues with this muscle loss.  Of critical importance is it reduces our overall health.  There is a strong correlation between maintenance of musculature and good health [4].  Secondly, loss of muscle leads to loss of joint support and thus mobility.

Old School rules!

How can we keep our musculature?

  • Eat enough protein.  Be generous: around 1g per kg of bodyweight a day.  At least 50% more than that if you are following good advice and taxing your system with resistance training.  And remember, 100g of meat is not 100g of protein!
  • Resistance training.  There are a thousand programs out there, but the concept of  simply lifting progressively heavier weights, incrementally, over the course of the years will ALWAYS achieve results. Be patient.  Stick with a program for an absolute minimum of 12 weeks.  Don’t rush to increase the poundage: it is better to make slow progress, keeping good form.   As a starter for ten, you should be aiming to lift heavy objects, i.e. weights that are difficult to lift, those that are a challenge, and challenge to your whole body – so particularly good are what are known as ‘compound’ moves, such as squats, deadlifts, presses, pull-ups and dips.  If you are new to resistance training, then that list of exercises is all you need to consider.

So how does resistance training manipulate hormone expression?  It does so by  reducing expression of myostatin and increasing levels of both testosterone and insulin-like growth factor (IGF-1).

What the hell are those?

  • Myostatin.  This protein is produced in skeletal muscle and it acts to  inhibit satellite cell proliferation (these are the cells, within the muscle, that have the potential to form new fibres).  It was discovered by investigating the cause of the ‘double muscled’ appearance of Belgian Blue cattle.  Resistance training has also been shown to reduce the expression of myostatin[5][6].  Myostatin levels can be reduced further with the aid of creatine supplementation [7].
  • Testosterone.  A steroidal hormone (derived from cholesterol) that is produced in the Leydig cells of the male testes, and in the theca cells of ovaries.  The exact mechanism of its hypertrophic effect on muscle mass is unclear [8], it may be due to its interaction with IGF-1.
  • IGF-1.  A protein responsible for the proliferation of satellite cells in the muscle tissue [9]. It is released in the liver, as a response to growth hormone, but it is also produced within skeletal muscle as a result of local muscular exertion [10].  In fact, in the absence of growth hormone, locally produced IGF-1 is enough to cause muscle gain (hypertrophy)[10].

So where should I start with resistance training?  Excellent resistance training resources I use are (no financial ties whatsoever):

Starting strength.  Mark Rippetoe gives an excellent introduction into strength training.  Concepts and fundamentals are covered in detail.

Jason Ferrugia‘s Muscle Gaining Secrets.  A newbie’s program, and one that focuses on simple progressive overload using compound moves.  Suitable for an athlete in any sport, or for those who are new to resistance training.  His blog and Facebook are regularly updated.

Primal Blueprint.  Mark Sisson’s take on Paleo, but included here on the basis of good, simple, strength training ideas.

Purposeful Primative.  Old school!

The Four Hour Body. Tim Ferriss’ n=1 experiment fest!  A lot of interesting ideas.

There you have it – tweak your lifestyle and see some results….!


1. Mattson, M.P. & Wan, R.: Beneficial effects of intermittent fasting and caloric restriction on the cardiovascular and cerebrovascular systems.  J Nutr Biochem. March 2005: 16 No. 3 129-137.

2. Varady, K.A. & Hellerstein, M.K.: Alternate-day fasting and chronic disease prevention: a review of human and animal trials.  Am J Clin Nutr.  2007:86 7-13.

3. Mattson, M.P.: Energy intake, meal frequency, and health: a neurobiological perspective.  Annu Rev Nutr.    2005:25 237-60.

4. Paddon-Jones, D. et al: Role of dietary protein in the sarcopenia of ageing.  Am J Clin Nutr.  2008:87 (Suppl) 1562S–6S.

5. Roth, S.M. et al: Myostatin gene expression is reduced in humans with heavy-resistance strength training: a brief communication. Exp Biol Med. June 203: 228 No.6 706-09.

6. Ryan, A.S. et al: Skeletal Muscle Hypertrophy and Muscle Myostatin Reduction After Resistive Training in Stroke Survivors. Stroke 2011: 42 416-20.

7. Saremi, A. et al:  Effects of oral creatine and resistance straining on serum myostatin and GASP-1. Mol Cell Endo.  2010: 317 Nos. 1-2 25-30.

8. Kraemer, W.J.et al: Effects of heavy-resistance training on hormonal response patterns in younger vs. older men. J App Physio.  Sept 1999: 87 No. 3 982-992.

9. Harridge, S.D.R.: Plasticity of human skeletal muscle: gene expression to in vivo function. Exp Physiol. 2006: 92 No. 5 783-797.

10. Borst, S.E. et al: Effects of resistance training on insulin like growth factor-1 and IGF binding proteins.  Med & Sci in Sport & Ex.  2001: 33 (4) 648-53.


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

  1. Pingback: Hunter Gathering in the press « finalprimate

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