The Montignac GI diet

One of the pioneers of using GI (glycaemic index) in relation to weight loss was Frenchman Michel Montignac. His diet has a large number of followers and is based on the glycaemic index of foods as well as food combinations.

How it works
According to Michel Montignac, combining certain foods makes you fat, and ultimately we don’t put on weight by eating too much but by eating badly. He sees weight gain as being linked to eating bad carbohydrates and bad food combinations.
The GI diet recommends cutting out foods with a high gylcaemic index (potatoes, carrots, beetroot, white bread, pasta etc), which produce lots of insulin, which in turn stimulates the growth of fat cells. Also off the menu are certain combinations of fatty and sugary foods or animal protein and starch. For example, chips are not allowed because they combine carbohydrate and fat. 
On the other hand, you can eat as much protein and fat as you like, as long as you eat them on their own. Fruit is allowed, but not with a meal. Cereals should be unrefined to reduce their glycaemic index. 

A typical day
Breakfast: Fruit, wholemeal bread with low-fat margarine, decaffeinated coffee, skimmed milk.
Lunch: Avocado vinaigrette, steak and green beans, cheese, still water.
Dinner: Salad or vegetable soup (no starch), mushroom omelette, green salad, fat-free fromage frais.

Results
Weight loss of at least 5 kilos per month.

Plus points
This diet allows you to lose weight without depriving yourself too much. You can eat out at  restaurants or at friends', enjoy sauces and desserts. Basically, there’s room for the odd indulgence with this diet.
You can start off gradually, and it's easy to carry out.
Unlike traditional diets, the Montignac diet allows you to eat as much as you want, provided that you choose the right foods and combinations.
Eating wholegrain, unrefined food is encouraged; these are really beneficial to health.

Downsides
The diet is sometimes too high in fat, which in the long term can be dangerous for the heart and arteries.
This diet doesn’t promote balanced eating, which is the sole way to guarantee good health.
It's too low in carbohydrates and causes tiredness.
The diet requires excellent knowledge of the nutritional composition of foods (good carbohydrates, bad carbohydrates, fat etc). 

In reality, the Montignac diet is a low-calorie diet in disguise: you lose weight quite simply because you eat less (25% less calories on average).