The reality is that the vast majority of people are unable to lose weight not because they lack self control but because the human body has evolved to cope with starvation and resist weight loss for survival! Our ancestors needed to be able to cope with food scarcity by conserving energy, and then gain weight when food was available to cope with the next food shortage.
Evidence has shown us that when we lose weight our body sees this as “starvation” and will lower the resting metabolic rate to conserve energy for vital functions such as heart beating, breathing and digestion of food etc. The body stops directing energy to less important functions so you might notice the following changes when dieting:
• Reduction in sex drive
• Menstruation cycle can stop or become irregular
• Hair loss
• Increased sensation of feeling cold all the time
• Increased lethargy/low energy levels
Averting energy to vital functions is one example of how your body tries to cope with inadequate energy. Additionally when food intake is restricted and energy expenditure increased (through exercise) our body starts to break down its stores of energy including fat and muscle. Loss of muscle mass further leads to our metabolism slowing down. Can you recall The Biggest Loser, an American TV show that followed a group of people who were classed as “morbidly obese” (BMI over 40) for 30 weeks? During this time the participants followed a 1200 calorie diet and exercised 6 out of 7 days.. Fast forward 6 years and most participants had regained 70% of the weight lost AND were burning 700 calories less per day when at rest (despite weight regain)! So they now needed to consumer fewer calories just to maintain their current weight and if they wanted to lose weight again they would need to reduce their intake even more to achieve similar weight loss results? Sound familiar?
Have you found with every subsequent diet you have needed to reduce your calorie intake further to achieve similar weight loss results?
Why does our body work so hard to prevent weight loss? Lets look at our genes.. We can all appreciate that we have a genetic predetermined height (and no one is trying to shrink their height!), similarly it is thought we have a predetermined weight range, termed the Set Point range.. This set point theory states our body has a preset weight range hardwired into our DNA; and whilst the environment can influence this i.e. undernutrition in childhood, our genetics largely influence our weight. So when we diet and lose weight, our body’s starvation defence mode kicks in and it tries its hardest to get the weight back to what it considers a “normal safe weight” i.e. our the set point range”. Evolution has ensured that our set point weight can go up but rarely can it go down. Remember when your mum told you life isn’t fair? This is most probably what she was talking about..
Trying to work against evolution and biology seems crazy doesn’t it?
