Gaining weight despite fasting? The glycemic index

Veröffentlicht am: October 30, 2024
Sarah Allen
Sarah Allen

Nutritionist and dietician

Are you gaining weight even though you are fasting? Have you tried almost all diets and just can't see any results? Then you are not alone!

The good news?

It seems that conventional medicine has found the reason why weight loss often does not occur despite persistent fasting. And the best thing is, you don't have to eat less to achieve your desired weight!

And what is the key to this?

The glycemic index

Contents

What is the glycemic index?

The glycaemic index is a number that provides information on how quickly the body converts carbohydrates into glucose. This means that two foods with an identical carbohydrate content can have a different glycemic index.

The smaller the number, the lower the effect on the blood sugar level:

  • 55 or less = low glycemic index (good for blood sugar levels)
  • 56- 69 = medium glycemic index
  • 70 or higher = high glycemic index (bad for the blood sugar level)

A comparison of these values offers the opportunity to choose healthier foods. An English muffin made from white wheat flour, for example, has a GI (glycemic index) of 77, while an English muffin made from wholemeal flour has a GI of just 45.

The glycemic index is sometimes indicated on the product packaging. You can also find a list of common foods on the internet. Harvard University lists more than 100 foods and their glycemic index. You can also obtain information about this from your dietician.

Foods that have not been processed at all or only minimally processed tend to have a lower glycemic index than refined or processed products.

The glycemic index was originally developed as a nutritional strategy for diabetics. An international GI database is maintained by the University of Sydney (Glycemic Index Research Services). The database contains the results compiled by researchers from various studies around the world.

How does the glycemic index work?

Some foods lead to a rapid rise in blood sugar levels. This is because certain carbohydrates such as granulated sugar or bread are more easily converted into glucose by the body. The body needs glucose for energy. In comparison, vegetables or wholegrain products are carbohydrates that are digested more slowly. So if you consume a large amount of easily digestible carbohydrates every day, you will find it difficult to keep your blood sugar levels under control despite insulin and other medication.

The glycaemic index allows you to differentiate between slowly breaking down "good carbohydrates" and quickly digestible "bad carbohydrates". This allows you to better control your blood sugar levels.

The Journal of Medical Association (JAMA) has admitted that weight gain does not depend on the number of calories, but on their type and how the body's insulin reacts to them. The JAMA admits that around 100 years of mainstream advice on obesity and weight gain has been completely wrong.

This is probably surprising news for conventional medicine, but nothing new for initiated nutritionists.

Foods with a high GI make you fat

The focus is on the body's insulin response and no longer on the amount of calories. JAMA explains this as follows: "The state of increased insulin response predictably leads to weight gain, while decreased insulin response promotes weight loss".

In other words:

  • If you eat foods that lead to a flood of insulin, you will gain weight.
  • Or vice versa: if you eat foods that do not trigger an insulin response, you will lose weight.

But how do we know which foods cause an increased insulin response? This is where the glycemic index (GI) comes in. Each food has its own glycemic index, which varies. Foods with a high glycemic index (GI) increase insulin levels and cause hunger hormones to go crazy. The more overweight you become, the more your body changes. Insulin no longer works efficiently and fat cells become more receptive to store even more fat. This means that even if you eat fewer calories, you will still put on weight as long as you eat foods with a high glycemic index. The conventional low-calorie diet therefore has a counterproductive effect: it reduces your energy intake, which in turn reduces the amount of energy you burn and makes you hungry. This creates a vicious circle: more weight gain, more hunger!

There is a way out

But there is a way out: eat foods that do not raise your blood sugar level or only raise it slightly. The lower your blood sugar remains, the less hungry you will feel. The glycemic index (GI) is a measure for determining the effect of a carbohydrate-containing food on the blood sugar level. The glycemic load (GL) on the other hand (see next point) takes into account the amount of carbohydrates per portion of a food. For everyday life, this makes much more sense than the pure GI.

The limits of the glycemic index

However, the glycemic index also has weaknesses. For example, it provides no indication of portion size.

For example, watermelon has a GI of 80 and would therefore be one of the foods you should avoid. However, a normal portion of watermelon only provides a very small amount of digestible carbohydrates. In other words, you would have to eat a lot of watermelon to significantly increase your blood sugar level.

Scientists have solved this problem by developing the numerical value of glycemic load (GL). This provides information about the increase in blood sugar levels when a normal portion is consumed. For example, a portion of watermelon (120 g) has a GL of 5 and is therefore a healthy food. In comparison, the GL for a portion of raw carrots (80 g) is 2.

The University of Sydney database lists not only the GI, but also the GL values. In general, the values are summarized as follows:

  • Low glycemic load: 1 to 10
  • Average glycemic load: 11 to 19
  • High glycemic load: 20 or more

We recommend foods that have a glycemic load of less than 10. Foods with a GL of 10 to 20 are ok, over 20 should remain the exception. These in particular increase insulin levels quickly, lead to weight gain and prevent weight loss. Instead, enjoy foods containing protein. Protein has a GL of zero.

Click on the link below to view the glycemic load table.

Here you will find a free download of the glycemic load.

Further problems

The glycemic index (GI) does not provide any information about other nutritional values. For example, the glycemic index of whole milk is 31 and the glycemic load (GL) for a glass (250 ml) is 4. However, whole milk has a high fat content and is therefore not the best choice for someone who wants to lose weight or maintain their weight.

Furthermore, the GI database is not exhaustive; it only contains the foods that have been researched. Many healthy foods with a low glycemic index do not appear in the database.

In addition, the same food may be listed with different GI values. Sometimes there is disagreement as to whether a particular food is healthy, so the database does not provide reliable information.

The glycemic index of each listed food is influenced by various factors, such as the method of preparation, the degree of processing and which other foods are consumed at the same time.

The glycemic index can change

The figure given is only valid on paper. On the plate, a food can reach a completely different value, depending on various factors.

  • Preparation: Fats, fiber and acids (e.g. lemon juice or vinegar) lower the glycemic index. The longer you cook starchy foods such as pasta, the higher the respective glycemic index.
  • Degree of ripeness: The glycemic index increases in fruits (e.g. bananas) with increasing degree of ripeness.
  • Other foods consumed at the same time: Lower the glycemic index of a meal by combining foods with a high index with others with a low index.
  • Your age, activity level and how quickly your body digests food will also affect how your body reacts to carbohydrates. If you suffer from a digestive disorder called gastroparesis, which often occurs as a result of diabetes, your stomach will be slow to empty. The body therefore absorbs food with a delay.

Classification of carbohydrates

Carbohydrates are an important part of diets. However, a distinction must be made between the different carbohydrates, as not all carbohydrate-rich foods are the same. The glycemic index (GI) classifies carbohydrates according to their strength and influence on blood sugar levels. Carbohydrates with a low GI value are digested, absorbed and metabolized more slowly. These cause the blood glucose (blood sugar level) to rise more slowly, which means that the insulin level does not rise too much.

A general overview of carbohydrates, blood glucose and the GI is useful for understanding glycemic index diets.

Carbohydrates are a type of nutrient contained in food. They are divided into sugar, starch and fiber. Whenever you eat carbohydrates, the body breaks down sugar and starch into a type of sugar called glucose. This is the main source of energy for the body's cells. Dietary fiber passes through our body undigested.

The pancreas releases two important hormones that regulate the glucose content in the blood. Insulin ensures that glucose is transported from the blood into the cells. Glucagon ensures that glucose stored in the liver is released into the bloodstream when blood sugar levels are low. In this way, the body is always supplied with sufficient energy and the natural balance of blood sugar levels is maintained.

Different carbohydrates are therefore digested by the body at different rates and released into the bloodstream as glucose.

What is a glycemic index diet?

With a glycemic index diet, you eat according to how much certain foods affect your blood sugar level.

The glycemic index is a system in which carbohydrate-containing foods are assigned a value according to the effect that the corresponding product has on blood sugar levels. The glycemic index itself is not yet a diet plan, but only one of many tools - such as calorie counting or counting carbohydrates - that should make it easier to select suitable foods.

The term "glycemic index diet" usually refers to a specific eating plan that uses the index as the main or only source for meal composition. Unlike other diets, a GI diet usually does not prescribe specific portion sizes or the optimal intake of calories, carbohydrates or fats that will lead to weight loss or weight maintenance.

Many popular commercial diets, nutrition guides or websites are based on the glycemic index, for example the Sears diet (Zone diet), "Sugar Busters" or the Slow Carb diet.

The purpose of a GI diet

The purpose of a glycemic index diet (GI diet) is to consume carbohydrate-rich foods that prevent sudden or high spikes in blood sugar levels. This diet can help you lose weight and prevent chronic obesity-related diseases such as diabetes and cardiovascular disease.

Reasons for a GI diet

Many people opt for a GI diet because they:

  • Want to lose weight or maintain a healthy body weight
  • Need help putting together healthier meals
  • Need help controlling their blood glucose levels as part of their diabetes management

Studies show that a GI diet can help with these goals.

Be sure to talk to your doctor before starting a weight loss diet. This is especially true if you suffer from certain diseases such as diabetes.

Details of the diet

On a GI diet, you mainly eat foods with a low GI. Here are some examples of foods with a low, medium and high GI value:

  • Low GI: green vegetables, most fruits, raw carrots, kidney beans, chickpeas, lentils and bran-based breakfast cereals
  • Medium GI: sweetcorn, bananas, raw pineapple, raisins, oat-based breakfast cereals, wholemeal, oat and rye bread
  • High GI: white rice, white bread and potatoes

In this context, commercial GI diets often refer to slow- and fast-digesting carbohydrates. In general, foods with a low GI are digested and absorbed more slowly than foods with a high GI value.

In commercial GI diets, recommendations vary in terms of portion sizes and protein and fat intake.

What results can you expect from a GI diet?

Every person is different and unique - so the results of a GI diet can also vary. Studies also show different results. The results you can expect depend on what you want to achieve with the diet.

Weight loss

The results of a long-term study (16 years), which looked at the diet of 120,000 men and women, were published in 2015. The scientists reported that those who mainly ate refined grains, starch and sugar with a high GL gained more weight on average.

Other studies show that a diet with low GI foods promotes weight loss and helps to maintain this weight. However, data from another study showed that individual GI values for some foods are subject to considerable variation. These fluctuations mean that the GI value is a very unreliable aid when it comes to choosing suitable foods. The GL should therefore also be taken into account.

Blood sugar control

Studies show that the total carbohydrate content is generally a better indicator of blood glucose levels than the GI. Carbohydrate counting has proven to be the best tool for diabetics to keep blood sugar under control.

In some clinical studies, however, a GI diet also proved effective and helped the diabetics involved to keep their blood sugar levels under control. However, a lower calorie intake and a high fiber content also had a positive effect.

Cholesterol

The review of studies measuring the effects of low GI diets on cholesterol levels provided fairly consistent evidence that such diets can help lower total cholesterol and LDL ("bad" cholesterol) levels - especially when combined with high fiber. Good sources of fiber with a low to medium GI are fruits and vegetables and whole grains.

Appetite control

One theory about the effects of a GI diet relates to appetite control. The theory is based on the idea that foods with a high GI cause a rapid rise in blood glucose levels, followed by a rapid insulin response and a rapid drop afterwards, which creates a feeling of hunger. With low GI foods, this feeling of hunger would be delayed. Clinical studies on this theory have produced mixed results.

If a GI diet could curb the appetite, everyone who eats accordingly would eat less in the long term and be able to maintain their weight better. However, there have not yet been any confirmatory long-term studies.

Conclusion

To maintain your current weight, you should only consume as many calories as you burn. To lose weight, you need to burn more calories than you consume. The best way to lose weight is to eat fewer calories and at the same time increase your level of exercise, for example by doing more sport.

Choosing foods based on their glycemic index or glycemic load can help you maintain your weight, as many foods that are part of a balanced, low-fat, healthy diet with minimally processed foods - whole grains, fruits, vegetables and low-fat dairy products - have a low GI value.

Some people benefit from a commercial GI diet because it gives them the guidance they need to make healthier food choices. However, the scientists who maintain the GI database point out that the "glycemic index should not be used in isolation" but that other nutritional information - calories, fats, fiber, vitamins and other nutrients - must also be considered.

In context: Glycemic load and good nutrition

The glycemic index should not be the only thing you should consider when choosing your food. Just because a product has a low glycemic index does not mean that it is healthy or that you should consume it in large quantities. Calories, vitamins and minerals should always be kept in mind.

For example, potato chips have a lower glycemic index than porridge oats and about the same as green peas. However, porridge and green peas contain more nutrients and are clearly healthier.

Portion size also plays a role. The more carbohydrates - regardless of which food you eat - the greater the effect on your blood sugar level. Statements on this are made using the glycemic load. This is a number that is often mentioned together with the glycemic index. In a sense, this is the glycemic index for a certain amount of a food.

The glycaemic load therefore provides information on both the quantity and quality of carbohydrates. Less than 10 is low, more than 20 is high.

Lower your glycemic load by taking this into account in your diet:

  • Eat more wholegrain products, nuts, pulses, fruit and vegetables without starch and other foods with a low glycemic index.
  • Eat fewer foods with a high glycemic index such as potatoes, white rice and white bread.
  • Eat less sugary foods including sweets, cookies, cakes and sweet drinks.

Of course, you can still eat foods with a high glycemic index. Simply enjoy smaller portions and combine them with nutrient-rich foods with a low glycemic index.

 

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