Why does a low GI diet help with weight loss?

Imagine a healthy and satisfying diet where blood sugar levels are stabilised, cravings are a thing of the past, and you lose weight and lower your risk of diabetes or heart disease in the process.  Here's why including foods with a low Glycemic Index (GI) in your diet is thought to be good for weight loss - and good for your health.

This article is written by Sarah Dawson, a freelance journalist and regular contributor to Private Health UK

If you want to lose weight you'll find a plethora of diets to choose from, and while some plans go out of fashion quicker than the latest designer handbag, others have more staying power.  The Glycemic Index (GI) diet is one such diet - believed by nutritionists and dieticians to be an effective programme for weight loss, and if followed correctly, for good health. 

The Glycemic Index (GI) is a system which tells you how fast eating a particular food will cause your blood sugar levels to increase.  It was developed by a professor researching dietary recommendations for diabetics.  GI is a ranking from 1 to 100 which measures the effect of a food on your blood-glucose level two hours after the food has been eaten.  Low GI foods have an index rating of 55 or less, medium GI foods a rating of 56 to 69 and high GI food a rating of 70 or more.  In short, food with a high GI will produce a sudden rush in blood sugar while food with a low GI will help your blood sugar remain stable - which is where you want it to be. 

Low GI diet foods 

Low GI foods include wheat bran, barley, oats, seeded and grainy bread, pasta, brown or white long grain rice and lentils.  Eating low GI foods can help with weight loss because they provide the body with a more balanced supply of energy so you will feel fuller for longer, and not feel the urge to raid the kitchen cupboards for snacks then doubtless put on lots of weight.  Carbohydrates like French Fries, potatoes, white bread and short grain rice have a high GI index providing the opposite effect. 

They have a fast and high blood sugar response, giving you an immediate boost but not satisfying you long term, so you will invariably feel hungry again quite soon after eating.  A high-GI diet causes a lot of insulin to be produced and an overload of insulin in the body makes it is easier to store fat.  This was beneficial in days gone by when we had to survive with irregular and unpredictable eating patterns, but it's not appropriate today as many of us overeat anyway, and it just means that the stored fat is harder to burn off.

When you digest carbohydrates such as starches and sugars they are converted into glucose (a form of sugar).  The rising levels in the blood trigger the pancreas to release the hormone insulin, which keeps the blood sugar levels stable and triggers the process of excess glucose being removed from the bloodstream.  Carbohydrates which break down slowly, releasing glucose gradually into the system have low Glycemic Indexes, and eating more of these means you can avoid dramatic falls in blood-glucose and enjoy a more steady stream of energy.  As a result, the low GI diet's smaller rise in blood sugar is beneficial for people with diabetes. 

Health professionals believe that having a consistently high blood sugar level can damage the small blood vessels and potentially increase the risk of disease in the small blood vessels of the heart, brain or kidneys while steady blood sugar levels will help reduce the likelihood of this occurring.  However, the Low GI diet is only a good way of controlling blood sugar levels if a balanced diet is followed.

GI diet celebrity followers

The basic premise of a low GI diet is that you should aim to eat more brown rice and wholemeal pasta, rather than white bread and keep 'treats' like cakes or crisps to a minimum.  One important point to be aware of is that the general nutrient content of a food will affect its GI.  Fat and protein for example affect the absorption of carbohydrate, and rather confusingly, this means that chocolate and full fat milk - which are both high in fat - have a low GI value! 

This doesn't give the green light to indulge in lots of low GI-rated chocolate and salty peanuts however - because saturated fats have a negative impact on your health and most GI weight loss diet plans recommend cutting down on saturated fats anyway.  A GI food chart shows the GI value of individual foods, and because only food items containing carbohydrate appear on the GI index you won't find meat, chicken, fish, eggs and cheese on the GI lists, but you will find processed foods if they contain flour.  The GI rating can be affected by the way your food is prepared or processed, and in the case of fruit, how ripe it is, but if you aim to include some low GI foods in each meal this will help to keep your blood sugar levels low and steady.

The rise in credibility of the Low GI weight loss diet has prompted the emergence of a handful of books by celebrity chefs - for example Antony Worrall Thompson has developed GI-friendly recipes in his book; The Diabetes Weight Loss Diet and The Low GI Diet Cookbook includes recipes by Rick Stein and Margaret Fulton based on 'smart-carb' as opposed to 'no-carb'.  Nutritionists believe that the GI diet can help prevent food cravings and over-eating while still enjoying a healthy, satisfying diet and many celebrities now favour the GI diet over the famous Atkins diet (the low- carbohydrate diet adapted by Dr Robert Atkins which took the dieting world by storm over the past few decades).  Apparently, the likes of Naomi Campbell, Kylie Minogue and Bill Clinton are all fans.

Profile of the author

Sarah Dawson is a Brighton based journalist who writes for national and international newspapers, magazines and websites. Sarah has worked as a journalist since 1997, mostly as a freelance.  Her articles have appeared in a diversity of publications from The Guardian to Red magazine.  Sarah specialises in health & wellbeing, holistic travel and lifestyle features.

View Sarah Dawson's website.

Get a quote for private surgery

We will submit your enquiry for information about a private operation, or the costs of private treatment to up to three healthcare providers in your local area.

Complete the enquiry form....

Find a consultant

Are you looking for a private specialist or private consultant in the UK? We maintain a database of around 2,500 UK specialists in private practice. You can search by specialty or postcode.

Read more....