Principles of the Montignac Method Scientifically Validated

In November 2001, a prestigious scientific journal, the British Journal of Nutrition, published a Canadian study which bears out the scientific premises behind the Montignac Method. (1)

The authors of this study are well known medical researchers at the University of Quebec. In 1996, the leading researcher, Professor Jean DUMESNIL, lost over 40 pounds thanks to the Montignac Method. Highly impressed by how this method had worked wonders for him, Dumesnil decided to probe more deeply into the principles underlying the Method.

With his team and the collaboration of two eminent colleagues (the nutritionist Prof. Angelo Temblay and Prof. Jean-Pierre Déprés, a specialist in lipid disorders), Prof. Dumensil set up a trial study designed to compare the Montignac Method with diets generally recommended by officially authorized medical professionals.

Twelve overweight volunteers with an average age of 47 and an average weight of 228.2 pounds (103.5 kg.) were recruited to take part in the study. Notwithstanding the fact that their Body Mass Index (BMI) was high at 33 kg/m², all of the volunteers were for all purposes in good health.

This group was subjected to three different diets, each lasting 6 days, with intervening recovery periods of two weeks. For each of the 6-day periods, all meals were taken at Quebec Laval Hospital Research Center Hospital. Everything they ate was precisely programmed and calculated under strict medical supervision.

Blood samples were taken at the onset and end of each of these experiments. During the last day, blood samples were taken every hour, in order to measure hourly variations in glucose, insulin and triglyceride levels during the course of a typical day.

The three diets chosen for the experiment were:

Diet 1 : This is the diet that is recommended by the American Heart Association (AHA). There are no limits on the amount of food that may be eaten, but lipid intake is low.

Diet 2 : This diet corresponded to the Montignac Method, which stresses we should only eat carbohydrates with a low Glycemic Index. As corresponds to the method’s application, there were no restrictions and participants were able to eat ad libitum.

Diet 3 : This diet was based on that recommended by the American Heart Association, except calorie intake was limited to the amount consumed spontaneously when the group was following Diet no.2, based on the Montignac Method.

The AHA diet was chosen because, in North America, it is used as a reference for the prevention of cardiovascular disease. Its principal objective has never been to help people lose weight. It was conceived principally to improve the balance of fats in the body. This is why it contains no restrictions regarding the amount of food that may be eaten. All the same, it is built on the same recommendations made by official nutritionists, that we should eat very little fat and lots of carbohydrates without distinction.

The initial assumption made by Dumesnil was that Diet 2 (the Montignac Method) would lead the participants to eat fewer calories than Diet 1 (AHA) despite the fact that in both cases they could eat ad libitum. When following the Montignac Method himself, he had noticed the satiogenic effect of the diet. In fact, he felt he ate quite enough. This satisfied feeling was proven to be true in other cases, as we shall see later.

As regards Diet 3, insofar as intake was limited to a specific number of calories, we could say that it was a restrictive version of the AHA diet, corresponding pretty closely to weight-losing diets prescribed in hospitals and by most traditional nutritionists.

The nutritional results

For each of the trial periods, the the average number of calories consumed as well as the proportional distribution of each of the macronutrients was noted. Similarly, the variation in weight and waist measurement over the six-day period was compared. These are indicated in the following table:


Diet 1

(AHA, unrestricted)

Diet 2

(Montignac unrestricted)

Diet 3

(AHA, restricted)






Waist size



















What we observe firstly is that the number of calories consumed in Diet 2 (Montignac) is 25% lower than in Diet 1 (AHA), even though, in both diets, participants could eat as much as they liked. This result is all the more surprising and significant, since reduced food intake with the Montignac diet occurred without any particular effort.

Professional nutritionists know that such an important reduction in caloric intake is not normally possible except with the aid of diet pills. Most of these, incidentally, have been taken off the market because of their risky side effects. Moreover, the questionnaires filled in by the participants at the end of each trial period, showed clearly they had eaten their fill whilst following the Montignac diet.

Comparatively, the questionnaires completed at the end of Diet 3 (the restrictive version of the AHA diet) clearly indicated that the participants were consistently hungry on this diet.. Some found it so difficult to cope with restrictions on the amount of food they could eat that they even asked to drop out of the tests. This reaction is entirely in form with usual reactions of rejection to low-calorie diets.

The weight-loss mechanism

The spontaneous reduction in caloric intake in Diet 2 (Montignac) is one of the reasons this dietary method is so successful. It is, in fact, very easy to follow, since it allows us to satisfy our urge to eat even when we eat less.

There are two explanations for this apparent paradox.

First of all, the amount of protein eaten spontaneously, is higher. Many studies have shown that proteins have a higher satiogenic effect than other foods. But above all, the carbohydrates eaten by those following the Montignac Method are chosen deliberately for their low glycemic index. Experience has shown that these carbohydrates are also quite effective in satisfying our urge to eat. What is more, by limiting our glycemic peaks, eating carbohydrates with a low glycemic index help us avoid reactive hypoglycaemia, which normally prolongs our feeling of hunger.

In terms of weight loss and waist measurement, Diet 2 (Montignac) shows the best results. It is twice as effective as Diet 3, although the number of calories eaten is identical.

Nutritional balance

It is interesting to observe how the nutritional balance of diets 2 and 3 differ from Diet 1.

The table below will help us to see this more clearly.


Diet 1

(AHA, unrestricted)

Diet 2

(Montignac unrestricted)

Diet 3

(AHA, restricted)


Proteins (Kcal)

Lipids (Kcal)

Carbohydrates (Kcal)

















If we refer to our control diet (Diet 1), we can see that the Montignac Method leads to a spontaneous reduction of 49% with respect to carbohydrate intake and 20% with respect to lipid intake, while protein intake increases by 55%.

According to Prof. Dumesnil, this is a potentially interesting dietary adjustment, particularly as the reductions are made at the expense of “bad lipids” and “bad carbohydrates”. Moreover, it has never been shown that this sort of increase in protein intake can have any adverse effects.

Insulin and glucose levels

In this study, Dumesnil felt it was important to point out the effects of one of the fundamental elements of the Montignac Method, to control insulin and sugar levels in the blood.

The graphs below show the hourly changes in glucose and insulin levels that were observed during the last day of each of the dietary periods.

Graph 1 shows peak blood glucose levels (glycemic peaks) generated by each of the three daily meals.  At breakfast time, the three diets induce a pronounced increase in blood sugar levels, though after lunch and dinner blood sugar levels are much lower for those following the Montignac Method. The higher glycemic peak in the morning, even with the Montignac Method, is explained by the fact that breakfast is predominantly a carbohydrate meal. As a result, the glycemic level is higher than with the other two meals.

Graph 2 clearly shows that insulin levels generated by the Montignac Method (even after breakfast) are always significantly lower than in the other two diets. Furthermore, at the end of the day, the insulin level is similar to what it was during the Montignac diet.

This point is particularly important, as it shows that the metabolic potential of foods matters more than their energy content. This is one of the fundamental principles underlying thee Montignac Method.

The results of this study clearly demonstrate that the Glycemic Index is a valid concept for substantially reducing glucose and insulin levels in the blood while, at the same time, helping to ensure an acceptable level of satiety. In this way, it is possible to reduce or prevent hyperinsulinism, which is a risk factor in diabetes, obesity and certain cardiovascular illnesses.

The lipid profile

Of all the results observed during the course of this study, those obtained in relation to cardiovascular risk factors are certainly the most spectacular.

The following tables summarize the effect of the three diets on lipid profile:

DIET 1 : The unrestricted American Heart Association diet.



After 6 days


Total cholesterol



Total cholesterol/HDL cholesterol ratio











* Indicates a significant statistical change

The significant statistical changes are the following:

  • A 10% reduction in HDL-cholesterol (“good” cholesterol) levels
  • A 9% reduction in the ratio of total cholesterol/HDL-cholesterol
  • A 28% increase in triglycerides.

All the above changes are negative and are, in fact, the reverse of the intended result.

We can therefore only conclude that this diet aggravates cardiovascular risk factors. At the same time, we should not forget that this diet is paradoxically, the one that is recommended by the most influential American authorities in matters relating to the prevention of cardiovascular disease. It is also the same diet that is prescribed most frequently to patients having a cardiac illness or showing signs of hypercholesterolemia.

DIET 2 : The Montignac Method



After 6 days


Total cholesterol



Total cholesterol/HDL cholesterol ratio











* Indicates a very significant statistical change


  • Here we can see that the level of HDL-cholesterol is unchanged. However, overall, the level of cholesterol goes down slightly. The ratio of total cholesterol/HDL-cholesterol therefore improves.
  • However, the most spectacular improvement relates to the level of triglycerides, which go down by 35%.
  • The difference between level on the last day of Diet 1 and the last day of Diet 2, is an even more significant 70%.

According to Prof. Dumesnil, there is no medication without side effects currently on the market that can bring about such a radical reduction in triglycerides is such short time (6 days).

DIET 3:  The American Heart Association diet, with caloric intake reduced to the level of Diet 2: that is, reduced by 25% with respect to Diet 1.



After 6 days


Total cholesterol



Total cholesterol/HDL cholesterol ratio











* Indicates a significant statistical change



The only significant change here is negative. There is, in fact, an increase in the Total cholesterol/HDL-cholesterol ratio, which runs counter to the effect desired and must therefore, be considered as harmful.

Other measurements


Insulin levels on an empty stomach and at the time of an induced hyperglycemia, was measured at the end of each dietary period.

A very significant reduction in these parameters was noted at the end of the Montignac diet, whereas there was no noticeable effect with the other two diets.

According to Prof. Dumesnil, these results indicate a reduction in hyperinsulinism and in insulin resistance after following the Montignac diet. This evidence is are all the more astonishing as it was observed after only six days. It therefore helps to corroborate the view, according to which insulin resistance (which lies at the heart of diabetes type II) undoubtedly has a nutritional origin.

The size of LDL molecules

In fact this parameter is already considered a fully-fledged, cardiovascular risk factor. Small size is seen as aggravating the risk factor and vice-versa.

After following the Montignac diet, it was noticed that the size of dense LDL molecules, had increased significantly, whereas no change was noted when following the other two diets.

According to Dumesnil, such a rapid, positive change had never been recorded before just by altering our diet.

In this context, it should be remembered that J.P. Despres (who participated in this study) described a particularly lethal metabolic triad that multiplies the risk of a coronary accident by a factor of 20.

It is particularly frequent in the case of men suffering with abdominal obesity and it is associated with:

  • hyperinsulinism
  • an increase in apolipoprotein B (which transport LDL-cholesterol)
  • an increase in the level of small, dense molecules of LDL-cholesterol.

Unfortunately, this lipid profile is fairly frequent. However, according to Prof. Dumesnil, the Montignac Method is particularly promising in these cases, all the more so as this type of patient often responds less well to dietary treatment and traditional medication.


This study confirms the suspicion that official nutritional advice built on theoretical models, is not based on facts and much less on results.. In certain cases, as we have seen, these results even run counter to what is intended.

This study shows moreover, that the Montignac Method with its stress on the metabolic potential of food (and particularly the Glycemic Index of carbohydrates), makes it possible to effect positive changes on various metabolic parameters within a very brief period of time (6 days). These positive changes include:

  • spontaneous caloric reduction while eating one’s fill
  • reduction of girth and weight
  • reduction of glycemia and insulin during the course of the day
  • reduction of insulin levels while fasting and during an induced hyperglycaemia
  • reduction in total cholesterol level
  • improvement in the ratio of total cholesterol over HDL-cholesterol
  • spectacular reduction of 35% in the level of triglycerides
  • increase in the size of dense LDL-cholesterol molecules.

And in consequence:

  • a reduction in hyperinsulinism and in insulin resistance.

This is why Prof. Dumesnil sustains that the Montignac Method allows us to lose weight effectively, without feeling hungry all the time (this is what makes it possible for a person to stay slim, to enjoy its long-lasting results), but moreover gives us a powerful means to prevent and even reduce the risk of cardiovascular disease and diabetes type II.

Naturally, even if the results of this study are promising, as a sound researcher, Prof. Dumesnil has decided to undertake a new study to verify the long term validity of his findings.

In one of his presentations, he concluded with these words:

“In this context, we must also recall the results of Prof. Walter Willett at Harvard University. Through his large-scale epidemiological studies (the Nurses Health Study, of 75,000 nurses over a period of 10 years, and the Health Professionals Study, involving more than 43,000 men), he has been able to demonstrate clearly that there is a direct relationship between the glycemic content of food and the risk of coronary disease and incidence of diabetes type II.

The results of this first study are therefore an important epidemiological confirmation of the premises underlying the Glycemic Index and the usefulness of GIs in promoting healthy eating habits. These studies are also indirect evidence that in all probability, insulin resistance and diabetes type II have a nutritional cause. The next stage is therefore to see how the concept of Glycemic Indexes can now be used on a long-term therapeutic basis.

(*)" Effect of a low-glycemic index – low fat – high protein diet on the atherogenic metabolic risk profile of abdominally obese men",

Jean G. Dumesnil, British Journal of Nutrition (2001), 86,
557-568 . Nov. 2001

Top of page