The answer probably lies in an area under a curve you have possibly never heard of. That curve can only be charted by way of a very specific test you have probably never heard of either - unless you are a borderline or diagnosed diabetic.
In the making of Cereal Killers, I undertook an Oral Glucose Tolerance Test (OGTT) to paint a picture of my ability to control blood sugar - or not. In a nutshell, you fast overnight then drink a sickly sweet elixir and draw blood every 30 mins for the next few hours to chart your body’s abilty to manage the onslaught. That gets sent off to a lab for analysis and comes back as a neat graph (mine is on page 6 here).
When Tim Noakes reviewed my results, he beamed and took great delight (as did I - or was that relief?) in telling me they were excellent. What's interesting is this - if we went back to do that again today, we would no doubt be discussing those results from a slightly different perspective.
Three years later, Noakes - and others - are now adamant that it is our Insulin response (as opposed to the simple Glucose response) to the OGTT that should be the focus of attention. It is Noakes’s firm belief that insulin resistance is the cause of all those middle aged marathon runner midriffs - and much more sinister metabolic disorders to boot.
Insulin resistance is a state where the body requires the release of more and more insulin to effectively manage blood glucose levels in response to a given level of food (principally carbohydrate) intake. It increases with age and in simple terms it is the reason why your 50 year old self cannot habitually slam a loaf of bread or a slurry of sports drinks without the distinct possibility of midriff exapansion.
Exercise - resistance training in particular - is proven to increase insulin sensitivity, but the food and drink we consume is the real driver.
If you are insulin resistant, the chances are it will catch up with you sooner or later (with or without exercise). This is where middle age spread meets that half marathon starting line. Equally, if you can find a bookie offering odds on someone with heart disease NOT displaying the signs of IR, take the bet. You will win.
The really interesting (and sinister) thing about IR is it’s ability to fly below radar for decades before eventually striking - like a health stealth bomber. In Tim Noakes’s case, that strike took the form of type 2 diabetes, the complications of which had claimed his father’s life.
Looking back at data from studies he had conducted some four decades ago, Noakes recently noticed that his own insulin response - at age 28 - CLEARLY demonstrated severe, underlying insulin resistance. In his own words, he had dismissed it at that time because he was carb loading to fuel a sub 3 hour marathon training regime. Sure, the tests showed he could get his blood glucose under control, but the insulin required to do that was (literally) off the scale.
In his not so ignorant bliss, Noakes (kinda) outran the carbs - and diabetes - for the next 20 years but then the weight crept on and his performances eventually reached the point of embarassment (for him - it’s all relative).
The stealth bomber had struck.
If feeding highly refined carbohydrates to a diabetic does not make much sense at all, then feeding them to a 45 year old insulin resistant amateur athlete shouldn’t either. The problem is, most amateur athletes have no idea they’re being stalked by the IR stealth bomber in the first place. The belief that they are outrunning whatever diet they choose is so prevalent that an additional inch or two round the waist won’t be setting of any alarm bells.
As for the elite athletes, Noakes holds the opinion that an integral piece of their pathology may well be insulin sensitivity. The ability to perform at super human levels requires an incredibly efficient fuel system (and a whole lot else of course) so any carbs available for performance in such an environment would get utilised optimally. This is yet to be proven but it is certainly an interesting hypothesis. Of course, as elite athletes age, all bets are off as IR may naturally increase anyway.
My own insulin response to the OGTT was measured for Cereal Killers so out of interest I fired it over to my fellow Irishman Ivor Cummins (aka the Fat Emperor) for some feedback. Ivor is an engineer/bichemist with an astounding grasp of all things insulin and a lot, lot more. His forthcoming book on the topic should enlighten many and most importantly shine a light on the remarkable life’s work of the 90 something (and active!) Dr Joseph Kraft.
That Kraft’s work has been largely ignored is not unusual. In fact, John Yudkin and sugar springs to mind. When we researched Cereal Killers, Yudkin's classic "Pure, White and Deadly" was not even in print. You see, Yudkin's views were not very popular at all for a very, very long time indeed but then they became very, very popular indeed after that. Today, he is the sage of sugar.
If Kraft is not very popular at all - yet - his time is certainly coming.
In the interim, stay tuned, remember the name, get up to speed on insulin.....and if you’re keen to banish that marathon midriff, just Run on Fat.