What Molecules Does Food Contain? - My Food My Future (2025)

Summary

• Lipids
• Carbohydrates
• Proteins
• Micronutrients
• Conclusion

To stay in good health, human need to eat to cover their nutritional requirements. All flavors, textures and odours of each food are associated with nutrients , which are food substances assimilated by the body and essential to its proper functioning. The aim of this article is to inform you about the molecules constituting food, from macronutrients (lipids, proteins, carbohydrates) to micronutrients (vitamins, minerals).

Proteins

• Role : structural (muscle, skin), immune response (antibodies), oxygen transport (hemoglobin), digestion (digestive enzymes) and source of energy
• Total energy intake from food : 15%

Lipids

• Role : Main structural components of cell membranes, sources of energy, essential for hormone production
• Total energy intake from food : 35%

Carbohydrates

• Role : Main source of energy in food (energy fuel)
• Total energy intake from food : 50%

Lipids

Dietary lipids are mainly triglycerides, being made up of 3 fatty acids* (FA). Fatty acids are distinguished by their structure : saturated fatty acids have no double bonds, while unsaturated fatty acids have one or more double bonds.

Excessive consumption of saturated fats, which mainly come from ultra-processed products, is associated with an increased cardiovascular risk. As a result, it is recommended to limit saturated fatty acids intake and favour un saturated fats, especially Omega 3 (oily fish, oleaginous fruits such asrapeseed, linseed, walnuts, etc.) and Omega 6 (vegetable oils, chia, walnuts, etc.).

Cholesterol is also sometimes pointed out, even though it is a vital lipid for the body (cell composition, vitamin production…). Its negative impact on health is not linked to cholesterol itself, but to its 2 transporters : LDL (low density lipoprotein) and HDL
(high density lipoprotein).

In fact, LDL transporters promote the accumulation of cholesterol in the arteries, thus increasing the risk of cardiovascular diseases, and are described as “bad”. Conversely, HDL transporters promote the elimination
of cholesterol present in the arteries and its transformation into bile*, and are thus commonly referred to as “good”.

Carbohydrates

Carbohydrates are the body’s main source of energy (50%). They are divided into two categories: simple and complex carbohydrates. Complex carbohydrates are distinguished by their large number of molecules (>2) and by their lack of sweetness compared to simple carbohydrates.

Simple carbohydrates can be naturally present in fruits and, conversely, can be
“added” in ultra-processed products such as cookies and sweets. The purpose of this addition is to improve taste, texture and shelf life of the product. Regarding added sugars, WHO recommends a consumption of less than10% of total energy intake
(ex: 50 g for an energy intake of 2000 kcal per day). Excessive sugar consumption can lead to overweight, obesity and related diseases, such as type 2 diabetes.

Carbohydrates can also be defined as fast or slow, depending on digestion time. Logically, complex carbohydrates, with a longer-chain, should be slower to digest. However, there are exceptions that make the use of these terms highly controversial in the scientific literature. Foods, such as boiled potatoes, made up of 80% starch, undergo rapid digestion. Although starch is a complex carbohydrate, it is rapidly broken down into glucose (a simple carbohydrate), leading to a rapid digestion, a sharp rise in blood sugar concentration and a high glycemic index (>70). In the case of wheat, the starch is protected by a protein network that makes it difficult to digest and so leading to a slower digestion.

Note : whole wheat still contains the bran (the husk that protects the grain), which slows down digestion and absorption, resulting in a lower GI than refined wheat (flour).

The complexity of carbohydrates (simple or complex) in no way predicts their speed of digestion and therefore whether they are slow or fast; the overall composition of the food
can modify the digestion capacity of carbohydrates.

Proteins

Proteins are macromolecules made up of a sequence of amino acids (AA). There are 20 AA which are present in dietary proteins, classified into 2 categories :

AA make up both plant and animal proteins. However, the AA composition of these two sources differs : animal proteins provide all the essential AA, while vegetable proteins do not.

Moreover, animal proteins have a digestion rate (the rate
which is absorbed by the body) of 90-99%. Plant proteins, on the other hand, have a lower absorption rate, because plants contain some compounds such as tannins and polyphenols, which can impact and reduce the digestibility of plant proteins. The digestibility of plant proteins varies widely, from 10 to 90%. However, plant sources remain indispensable, notably for their micronutrients (vitamins and minerals) and fibers.

Note : Food products of animal origin have a higher protein content : 100g of beef steak provide 27g of protein, compared with 6g for wheat and 10g for kidney beans.

Micronutrients

Micronutrients do not provide energy, but are essential for the body’s proper functioning.
Micronutrients are minerals (e.g. calcium, potassium, magnesium, copper…) and vitamins (vitamins A, C, D, E…). Some of these have antioxidant properties that can prevent cellular
aging.

Note : The shift from whole foods to processed and refined foods reduces the quantity of micronutrients in the modern Western diet, leading to deficiencies in the world’s population and increasing the risk of some pathologies (obesity, cancer…).