I spend an unexpectedly inordinate amount of my professional life discussing weight and how to lose it. And to be honest, I really enjoy this part of my practice. It’s a mix of motivation, teaching and finger pointing. Ok, creative licence on the finger pointing…I don’t do much of that, unless an athlete is really asking for it!

As a guesstimate, roughly one third of my practice is treating foot and ankle injuries in non-athletes. Or more accurately, less than serious athletes. These are caused in the great majority by compounding formative injuries in mainstream sports (football, netball) with middle age spread. So an untreated sprained ankle leads to instability, which with the passage of time (and weight gain) accumulates joint injury. Patient then discusses inability to exercise due to pain as reason for overweight or obese status. I produce venn diagrams, as explained below.

The other two-thirds of athletes I see are serious about sport. Shoulders sore from swimming, ITB related knee pain, back stiffness, achilles tendonopathy and race-nutrition failure. Oh and man-flu! Nonetheless this group is still plagued by the confluence of weight gain, accumulated injuries and gravity. This impacts their ability to stay on the training track and perform well on race day. But how light should we be? And for what purpose?

The Science

Fact 1. An average Australian accumulates one gram of fat per day from the age of thirty to sixty years of age. That’s one kilogram every three years, by ten. Yes, math says a ten kilogram weight gain.

Fact 2. Next let’s account for ground reaction force (GRF). It’s Newtons third law, which states that for every action there is an equal and opposite reaction. Without digressing too much, walking on flat terrain sees 1-2 X gravity and running 2-4 X gravity. Jogging is at the highest end of GRF, whereas running quickly sees a reduction from that peak.

An experience mathlete can calculate that an average middle aged man (80kg) will experience up to 320kg of GRF whilst running. Given that 5kg of this is accumulated fat (6% of body weight)- so 20kg of excess/unecessary GRF per foot fall. Over an hour run (60minutes) with an expected 80 foot falls (40L/40R) that accumulates to a horrifying 48 000kg of excess GRF for each of your left and right ankle/hip/knee joints.

Fact 3.

The average human expends 2000 calories of energy per day. This doesn’t vary much, except when you take into account heavy exercise. Like triathlon training. Which means athletes need to eat more calories to maintain effort during exercise or recover from their training. Without recovery, performance will not improve. Training makes you hungry. Athletes eat calories to match their energy expenditure, and then some. See Fact 1 and 4. So even though weight = energy in + energy out, it ends up being skewed by hunger and satiety.

Fact 4.

Hunger/satiety is controlled centrally by the hypothalamus- a critical part of your brain that is also responsible for metabolism, thirst, body temperature, fatigue, sleep and circadian rhythms. Please note, the hypothalamus and recovery from fatigue are intimately linked. This portion of brain relies on a host of feedback mechanisms to do it’s job (largely hormonal- including grehlin and leptin). Grehlin is released from your gut when it is full (i.e. on stretch), and Leptin from fat cells (when they are full of fat). Simply put when your gut and fat cells are full, the hypothalamus is signalled that you don’t need to eat anymore. Except modern man is plagued by miscommunication- thus the accumulation of 10kg over 30 years.


Weight is an emotional issue for women and men. But as athletes we need to make decisions about exercise as dispassionately as possible. Think about what your body composition is and match your activity levels and thus race expectations to that reality. Training for your size will reduce the risk of injury and keep you happily training and racing (See fact 2). Run a little (or a lot less), walk and do plenty of swim/biking.

Your weight is a function of what you eat, not what you do (by enlarge). Examine Venn diagrams below.

People as a general rule (athletes included) have been programmed to think that if you want to lose weight (spend energy> eat energy), you just need to get out and exercise more. Thus Venn 1. where there is intersection between exercise and diet. And this would be true if we didn’t have Fact 4.

The reality is that weight is really only related to what you eat. Exercise is for mental health, stimulating the brain and body with endorphins plus enjoying the social aspects. It keeps us both sane and healthy. It is a leisure activity with the fringe benefit of keeping your body and mind healthy. Not a bludgeoning tool for making your body the weight and shape you want it to be. It has to be F-U-N!

Food choices are responsible for your calorie intake and your resultant weight. It is also responsible for your ability to recover, replace glycogen and damaged muscle proteins. This doesn’t have to be fun. It should from time to time be enjoyable, but food is largely for function. Take for instance a gel: function>fun, but it helps with exercise so we tolerate the taste/consistency. Salad is function>fun, just like a gel. It clears the bowel, fills you up and provides nutrition. Donut is just fun. Not function. It’s like going to the movies- doesn’t happen every day, a treat.

Practical Advice

Training for racing is difficult. It involves many sacrifices- time, money and energy. In addition, losing weight is a brutal affair: it takes time and energy to cope with hunger. Trying to mix the two is a recipe for disaster. Emotional show-downs happen when these two issues collide. I have had more than my share of personal clashes due to a coalition of hunger, thirst and tiredness. It’s a dead set axis of evil!

So try and divide the emotional from the factual. You are the athlete you weigh at the moment, so shoot for exercise that suits. If you are a healthy weight and uninjured, then carry on! If not, try to lose weight slowly, not binge dieting, so you avoid the weight gain of an average Australian. Or even maintain your current weight and enjoy exercise that suits your physique. Your body needs to last 100 years, not 100 triathlons.


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