With spring, the cravings for the beach, light outfits… and diets return. Very popular in recent years, a practice is to favor foods with a low glycemic index (GI). What interest? Is this diet more effective than another? How to put it into practice? The explanations of Sophie Schaeffer, micronutritonist.
A definition of the glycemic index, to begin with?
It is a carbohydrate quality index, which reflects the ability of different foods to raise blood sugar levels more or less quickly, and therefore to cause the pancreas to secrete insulin.
What is the benefit of a low GI diet?
On an empty stomach, blood glucose (in other words the amount of sugar in the blood) fluctuates between 0.7 and 1.1 grams of glucose per liter of blood. When we eat, blood sugar rises as a result of the digestion of carbohydrates. The advantage of choosing low GI foods is to avoid too high and too frequent peaks in blood sugar, which are harmful insofar as they overstimulate the pancreas and make insulin (which regulates the rate of blood sugar) less efficient.
What are the short and medium term effects?
In the short term, eating low GI foods prevents cravings between meals and the fatigue that goes with it. It is indeed wrongly thought that in case of sudden fatigue, it is necessary to eat sugar (glucose); it is a myth. By doing this, we will have the impression of getting better for a short time but very quickly, when the sugar level will drop in the blood, we will find ourselves in hypoglycemia, and paradoxically, we will feel more tired.
In the longer term, favoring a low GI diet helps fight once morest overweight and obesity. The body has a capacity to store sugar in the liver and in the muscles (glycogeny) which is not extensible.
Also, when the reserves are reached, this sugar is assimilated via other storage pathways, in the form of adipocytes, which leads to adipose, in other words an abnormal fatty accumulation in the body. This is what makes the bed of overweight, and at the same time of the pathologies linked to it: diabetes, NASH (fatty liver)…
Effects other than weight?
It is less known, but the overload of cells with glucose accelerates aging. Normally, mitochondria in cells combine glucose and oxygen to produce ATP, which provides the energy the body needs.
But when the cells are overwhelmed by the quantities of glucose, they produce free radicals, which are in a way “the rust” of the body, since they cause the oxidative stress at the origin of aging. As a bonus, the association of this oxidative stress with the caramelization of the body caused by sugar (which is called glycation or Maillard reaction) makes the bed of all the diseases of civilization.
Should we therefore encourage people to follow a low GI diet?
Yes, even if we cannot speak of a diet strictly speaking, insofar as there are neither restrictions nor prohibitions. We eat everything. We simply avoid excesses. “Everything is poison, nothing is poison, the dose alone makes the poison”, said Paracelsus. Preferably eating foods with a low GI is just a healthy way to eat. And that’s more or less the way our grandparents ate: unrefined grains, fruits and vegetables, and mostly raw, unprocessed foods.
Concretely, which foods to favor?
We favor semi-complete or complete cereals (rice, spelled, quinoa, etc.) and legumes, in short, everything that is rich in fiber. The reason is twofold: what most increases the glycemic index of foods is their transformation, refining; on the other hand, the fibers will slow down digestion and therefore contribute to “smooth” the curve of glycemia.
Eat vegetables and fruits, whole rather than juices or smoothies, to preserve fiber. We use good fats: olive oil, rapeseed, nuts… The fat will “dress” the carbohydrates and also slow down their digestion. And above all, therefore, avoid ultra-processed products: they contain less fiber; manufacturers often add fructose, which is even worse than glucose in terms of glycation; and food processing and cooking processes raise their GI.
The right low GI plate?
Half vegetables, a quarter protein and a quarter low GI starches.
Is it enough to lose weight or not to gain it?
No! A study – detailed in the book Make your glucose revolution by Jessie Inchauspé (1) – shows that choosing low GI foods is not enough. The order in which food is ingested, how it is cooked and of course the quantity that is consumed modify the glycemic load. For the same meal, the glycemia curve will not be the same depending on whether you started with vegetables or starchy foods!
The basic advice for optimizing a low GI diet?
Ideally, we start with vegetables or raw vegetables. Then proteins, and finally starches. And we do not lose sight of another essential point: moving following the meal also modifies, downwards, the glycemic load. When people have understood this, the first effect they notice is a reduction in fatigue.
1. Make your glucose revolution by Jessie Inchauspé, Robert Laffont editions.
Three tips for optimizing your low GI diet
Cooking and raw rather than cooked
Cooking raises the glycemic index of foods. So beware of overcooked foods (rice or pasta), and all pre-cooked foods! We don’t eat them alone: to lower their GI and slow down their digestion, we add a little olive oil (yes, it’s counter-intuitive!). In the same vein, an apple or grated carrots have a lower GI than a compote or steamed carrots. A compote at snack time is almost like candy for blood sugar!
Sweet… for dessert rather than snacks
Absorbed following a meal, a little sweet treat will contribute less to raising blood sugar than if it is eaten on its own, in the middle of the followingnoon.
Watch out for breakfast
“This is the meal that conditions the most blood sugar during the day. If we trigger a glycemic peak in the morning, all day, it will be a roller coaster. Hence the interest of a salty breakfast with sourdough bread, oatmeal and especially protein and fat.”
