Diet Vs Exercise: How to maintain weight after surgery

By Consultant Plastic & Reconstructive Surgeon, Oliver Harley

Being a healthy weight is the best way to feel and look your best and, if you are considering surgery it can contribute to the safety and the success of your operation.  It is a really difficult challenge to lose those pounds with such a baffling array of advice, diets and programmes constantly bombarding us……and all the while so many appetising excuses to eat and drink and put off that diet for just one more day……and so little time to get out there and take exercise.

Let’s say you want to lose a ‘stone’ – what is a ‘stone’? It is 14lb…..fourteen imperial pounds, which converts to 6.4 kilograms.  Eat less, exercise more or a bit of both?  There have been a number of studies in recent years which explore exactly this question.  A combination of both calorie restriction AND exercise appears to be the most effective; dieting alone is the next best and exercise alone is the least successful option.  So, if you have to make a choice, choose dieting over exercise, but its most effective if you can do both at the same time.  It is probably the case that if you diet without exercising, you may also lose some muscle bulk as well as losing fat; if muscles are being well exercised, your body should automatically preserve muscle bulk and use up more fat.  Exercise, of course, has plenty of other physical and psychological health benefits. 

What are calories and how do I get rid of them?  A food calorie (abbreviation ‘kcal’) is a measure of energy content in food.  Food packages will also show energy content in kilojoules ‘kJ’ – this is a modern measure of food energy but most people are more familiar with the idea of calories.  Your body needs energy (calories) to survive: A 5’6” female with a sedentary lifestyle needs approximately 1700 calories per day and this might rise to 2400 with a very active lifestyle or physical job).  If you consume more calories than required for daily living, your body saves these up by converting them to fat- you put on weight.  If you consume less calories than you need for daily activities, your body makes up the difference by breaking down its fat stores- you lose weight.

As an example, during the morning and lunchtime I was writing this piece, disgracefully snacking and multitasking, I had a brioche roll (126kcal), 3 digestive biscuits (213kcal), a cafe latte (128kcal), smoothie (55kcal), apple (47kcal), sausage roll (180kcal) – total – 749kcal. During this time, even at rest, my body would have used up perhaps 500kcal and if I had found 30 mins to walk the dog, I might have burned off an additional 120 kcal… So maybe I put on a bit of weight during these few hours… But how much weight?! One pound of fat is equivalent to 3500 calories and I had 249 calories more than required so I may have gained an ounce in weight.

A reasonable diet and exercise strategy might aim to have a calorie intake of perhaps 500kcal less than daily requirements… So you would lose 500 calories worth of fat per day:  Therefore 3500 calories per pound of fat; divide by 500 gives you 7.  This means you might shed a 7th of a pound per day and so a whole pound per week.  Continue this level of dedication for fourteen weeks and you have lost a stone.  By my standards this could mean just 30 mins daily walk (120 kcal burned off) and cutting out 3 biscuits (213kcal less intake) and a sausage roll (180kcal less intake) from your daily diet.  Hooray. 

For more information see NHS calorie counter on or download an NHS choices weight-loss pack