We are often told a “calorie is a calorie” and the way to get fit and lose weight is by controlling our calorie (or energy) intake.

General advice is that men need about 2500 KCal per day and women about 2000 KCal per day – however these guidelines are anything but scientific – the Food and Drug Administration (FDA) established these figures from self reported daily consumption levels in the 1990s and measured these against fluctuations in (self reported) weight.

To get back to the science, the body only uses carbohydrates and (to a lesser degree) fat to fuel the body (or metabolism).  Protein is only used in extreme situations to be burnt in metabolism – it’s main function being repair and renewal of cells and structures.

It has been seen that the healthiest of people have the ability to change quickly from burning carbohydrates to fats when sugars are exhausted.  This is called metabolic flexibility and is associated with correct weight maintenance, reduced risk of diabetes, metabolic syndrome, heart disease, stroke and even dementia and cancer

On the other hand, the most unhealthy people tend to only burn carbs all day and suffer from numerous co-morbidities.  They have to consume large amounts of carbohydrates just to keep going. 

So how can we become more metabolically fit and flexible.  Well initial studies seem to indicate that –

• Fasting may help – either one or two fasts per week OR fasting “windows” where we only eat for 8 to 10 hours per day.
• Reducing carbohydrates in our diet and replacing it with quality fats and proteins can work
• High Intensity Interval Training (HIIT) often “shocks” the body into fat burning
• Cold therapy can speed up metabolism, activates brown fat stores and therapeutically stress the body so it begins to use fats for energy.