What’s Realistic? – A Guide to Effective Weight Loss

Many people start out on a journey to lose weight with unrealistic expectations that not only can’t be reached in a healthful way, but also, can’t be maintained. That is, by far the majority of people that lose weight rapidly, put the weight (and often more) back on. You may have taken a decade or two to put on 10 or 20 or 30 kg, you should not expect to lose it in an unrealistic short timeframe.

For most people, a loss of 500 grams per week is realistic. This may be a little more if you have more weight to lose, and less when you approach your ideal weight. Your body has a natural ‘set point’ and will naturally try to maintain what it thinks is your natural weight. This ‘set point’ needs to be naturally adjusted gradually. Also, when you lose weight too quickly, especially when you do it with diet alone, you will lose muscle mass which affects your metabolism. This in turn makes it increasingly difficult to lose weight but also causes you to put weight (with a bit extra) back on. This cycle of dieting decreasing metabolism dieting etc. is very difficult to turn around.

How Much Do You Really Need to Eat?

If you eat exactly the number of calories your body needs for your basal metabolism and physical activity, your weight will remain stable. Weight gain will occur when you consume more calories than your body burns. These extra calories are converted into fat and stored within your body. Approximately 50% of fat is stored under the skin. Conversely, if you use more energy than you take in, you will lose weight. To lose, 1 kilogram of weight, you need to expend 7700 calories more than you consume.

Calculate your daily requirements

Firstly, calculate what your daily requirements are and then manage your eating intake (e.g. food choices, portion sizes and frequency of meals) accordingly. If the energy consumed is not used, the balance will be stored as fat.

You can assess how many calories your body requires by calculating your Basal Metabolic Rate (BMR). Your BMR is the amount of energy (calories) that your body needs to function and maintain itself. You can then use this information to calculate how many calories you need to consume to lose weight or maintain a particular weight. For fat loss, the aim is to expend more calories than you consume. To achieve a weight loss of ½ kg per week the deficit needs to be 550 calories per day. The aim should generally be a deficit of 500–1000 calories per day. This can be more if you weigh more than 130 kg. Minimum calorie intake should be 1200 for women and 1600 for men. This however, will be dependent upon your size.

Note: Calorie restriction (without exercise) may lead to greater fat storage. During moderate caloric restriction, exercise helps maintains your BMR.

You can use the formula below to calculate your BMR.

BMR = {[9.99 x weight (kg)] + [6.25 x height (cm)] – [4.92 x age (years)] + S} x activity factor

where S is +5 for males and –161 for females.

Activity Factor

1.2 Sedentary (little or no exercise, desk job)
1.375 Lightly active (light exercise/sports one to three days/week)
1.55 Moderately active (moderate exercise/sports three to five days/week)
1.725 Very active (hard exercise/sports six to seven days/week)
1.9 Extremely active (hard daily exercise/sports, or two times/day training)

The ideal macronutrient breakdown

Providing you restrict your calorie intake to the amount calculated, you will lose weight. This will not, however, allow your body to necessarily perform optimally. Your body requires certain amounts of protein, carbohydrates and fats and the balance of these is very important. Our bodies convert food into energy and nutrients from these macronutrients in order to perform our daily functions. Focus on nutrition for optimal performance and weight loss will happen.

Even racehorses are fed quality food in precise portions to get the best from the horse. Shouldn’t you treat yourself just as well?

In summary, the macronutrient requirements for optimal weight loss and health are:

  • Protein – 1.05 g per kilogram of body weight
  • Fat – 20 - 30% of your overall calorie intake (Use 25% for your calculation)
  • Carbohydrates – The remainder of your calorie intake will come from carbohydrates. This will generally be (but is determined by your overall weight) 50–60% of total calories.

Exercise is the foremost predictor of weight loss success (including maintenance), i.e. people who commit to exercise are the ones who are the most successful. With this commitment often comes an increased discipline in food choices and other factors that affect weight loss. It is imperative that you plan regular physical activity that can be maintained. The common barriers that people have are lack of time, lack of facilities, lack of money or lack of workout partners. Do whatever you need to do to include exercise in your daily life.