30 May 2011

Carbs and weight loss

There is a lot of confusion about what to eat or not eat when trying to lose weight. Registered dietician Karen Protheroe gives some perspective.


There is a lot of confusion about what to eat or not eat when trying to lose weight. We are all very aware of the "no carbohydrate diets" which result in rapid weight loss and an even more rapid weight gain when you eventually fail to continue with this very difficult diet. ( “Diet” is low in carbohydrates, it is not an eating plan that can become a way of life.) 

On the other end of the spectrum there are diets that tell you to eat as many sweets, breads, muffins, pasta, etc., as you like, as well as eating as much sugar, fructose, honey and molasses as you can. In other words you can eat as much carbohydrate as you want as long as it is fat-free. The theory behind this type of diet has its pros and cons. Lets start by looking at the positive.

Firstly if you increase your intake of carbohydrates, your body automatically increases its ability to burn those carbohydrates. This essentially means that your body will automatically neutralise the excess intake rather than storing it as fat. Important: the same does not apply to excess fat intake – this means that any increased intake of fat will result in increased fat storage rather than increased fat burning.

Secondly, if you overindulge on carbohydrates today, your carbohydrate stores get filled up and your body automatically signals to you to eat less carbohydrate tomorrow. Again the same does not apply to fat intake, as your body’s ability to store fat is endless.

Thirdly, it has been shown that those eating a high carbohydrate diet automatically eat less fat, while those eating a low carbohydrate diet take in much more fat (usually a diet low in carbohydrate is high in protein and this on it’s own can result in a high-fat diet).

So, the question that is on everyone’s lips is - does this mean we can eat as much carbohydrate as we want and still lose weight? Those who have tried sticking to this kind of diet all have a similar story. That is they lose a few kilograms initially and then no more. Again, there are several reasons for this.

The initial weight loss occurs because of cutting the fats out of your diet. Then, if you eat excessive amounts of carbohydrate (must be low fat or even fat-free), then the body will just increase its carbohydrate burning ability and therefore use up whatever carbohydrate you eat for energy. The body will not need to turn to its own fat stores for energy as all the energy it needs is coming from the excessive carbohydrate intake. This therefore means that you will maintain your weight rather than lose any weight.

The other problem with many people who eat a very sugary diet, is that eating sweets and sugary foods as opposed to a sandwich or crackers and cottage cheese (the first is called a simple carbohydrate and the second group are complex carbohydrates), can result in fluctuating, unstable blood sugars as well as an increase in triglycerides (a bad fat found in one's blood). Unstable blood sugars result in difficulty in controlling your appetite and cravings and fluctuating energy levels and moods. Also one needs to eat proteins and healthy fats to meet one's nutritional needs.

Therefore, the take home message for weight loss is: eat a diet moderately high in carbohydrate (concentrating on the complex form which is wholewheat bread, wholewheat pasta, potatoes, legumes, fruit, vegetables, wholewheat cereals and so on, as opposed to sugary foods) and moderate intakes of protein and fat. Your dietician will be able to establish the correct balance for you depending on whether you want to lose body fat or maintain your body fat.

- (Health24, updated May 2011)

This article was written by Karen Protheroe, registered dietician of The Lean Aubergine Dietetic Services.

To sign up for the monthly Lean Aubergine Dietetic Services newsletter, send an e-mail to Karen Protheroe.

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