What is the FMI?
The fat mass index is a measure of the proportion of body fat in relation to total body weight.
Would you like to find out all about the Fat Mass Index (FMI)? Is it a reliable and useful indicator? Let’s dive in.
The fat mass index, less well-known than the body mass index can be just as useful for weight and health purposes. What does it involve, and what are its advantages and limitations? Dietician Julie Guéry explains.
The fat mass index is a measure of the proportion of body fat in relation to total body weight.
To find out your body fat percentage, Julie Guéry suggests three methods.
◾ THE DEURENBERG FORMULA
The first, the most common and accessible, is the Deurenberg formula. This calculation is based on BMI (body mass index), age and sex. "It's not the most reliable method,' our specialist explains. It is based on averages and therefore has a greater margin of error."
To calculate your body fat percentage, the formula is as follows:
For women: BFI (in %) = (1.20 x BMI) + (0.23 x Age) - (10.8∗gender) 5.4.
For men: BFI (in %) = (1.20 x BMI) + (0.23 x Age) - (10.8∗gender) 5.4.
with gender:0 for a woman and 1 for a man.
You can then compare your results using the table below.
◾ SKIN FOLDS
Another method is skin folds. "This method makes it possible to measure the percentage of fat mass present in the body and to monitor its evolution in the context of weight loss or lean bodybuilding. This involves using a pair of callipers (manual or electronic) to measure the thickness of four fat folds located on the body.” The four main folds are located on the back of the upper arm, under the lower angle of the shoulder blade, on the front of the upper arm and about 5 cm from the navel. Using these figures and an equation determined by age, gender and the data from the four main folds, the body fat percentage can be determined. "The skinfold method is the most reliable way of obtaining your body fat percentage, provided that the folds are measured regularly in the same place, which is why it's so important to be supervised by a professional.”
◾ IMPEDANCEMETRY SCALES
Finally, the last method: impedancemetry scales. "By passing an electrical current through the body, these scales can calculate all the components of the body, such as water content, muscle mass, bone mass, and sometimes even the weight of the viscera and therefore also the percentage of body fat, explains Julie Guéry.I recommend impedancemetry scales where the electrical signals are recorded from the feet and hands, giving a more global analysis of the body.”
Our dietician nutritionist adds a few tips to ensure that this result is as reliable and accurate as possible: "this calculation should be made several times, at regular intervals and under the same sporting and nutritional conditions. A word of caution: it's not the most reliable method, but the result can give an idea of the overall trend in body fat. The scales are not suitable for people with pacemakers, pregnant women and children."
When body fat levels are too high, fat is stored around the organs and in certain areas of the body (stomach, waist, hips, thighs). "Over time, this can lead to excess weight or even obesity, which can make it difficult to move around and be independent, explains Julie Guery. Shortness of breath can occur, as can joint problems. This can lead to cardiovascular disease, blood pressure disorders, high cholesterol, high triglycerides and diabetes. High body fat percentage also contributes to liver, intestinal and digestive disorders. Sometimes, without an established health problem, psychological distress can also occur."
The Body Mass Index and the Fat Mass Index are linked. What is BMI and how is it calculated? Find out everything you need to know.
The Body Fat Index (BFI) is a more recent measurement than the Body Mass Index (BMI).
BMI gives you your weight to height ratio, but doesn't tell you what that weight is made up of. Let's take the example of a sportsperson. Their BMI may be increased because of their high muscle mass, and they may be considered overweight according to WHO guidelines.
This is where the FMI is useful and more accurate (if the method used is also accurate), by determining the fat content of the body.
The FMI is not 100% reliable. It takes into account average data, and does not apply, for example, to pregnant women or young people under the age of fifteen. "Growth, hormones and the menopause can have a major influence on the results, explains our specialist. That's why it's so important not to rely solely on the raw data, but also on how it evolves."
In sport, the fat mass index needs to be viewed in a different light. The FMI is directly related to the BMI, which itself is not 100% reliable. "An athlete may be considered obese according to their FMI because their muscle mass is much higher than average. Take, for example, a judoka who is 2 metres tall and weighs 140 kg. If you calculate his fat mass index, he is considered to be obese."
What matters to the sportsperson is not the result itself. "What matters is the analysis of the result as a whole. What changes have occurred between two dates?How fit and healthy does the athlete feel? These are the elements that are important for sportspeople to take into account."
Would you like to know your daily calorie requirement? Follow our advice.
"It's quite difficult to lose body fat alone, warns our specialist. To do this, you need to review your lifestyle and adapt it to your goals."
🔸 First factor: nutrition. "To lose body fat, you need to limit saturated fats (found in red meats, cheeses, and sunflower oil, for example), and refined sugars (sweets, chocolate bars, cakes, pastries). Eat a balanced diet with good quality proteins (vegetable or low-fat animal), good quality vegetable fats providing omega 3 (olive oil, rapeseed oil, salmon and small oily fish, such as sardines and mackerel) and raw and cooked vegetables." Low glycaemic index carbohydrates are also recommended. They prevent snacking by balancing blood sugar levels.
🔸 The second factor is sporting activity. "To promote fat loss, you should take part in sports that stimulate the cardiovascular system to reach 70% of your maximum heart rate (MHR) for 45 minutes to 1 hour, 3 to 4 times a week. These conditions will encourage lipolysis, the mechanism the body uses to break down fat so that it can be absorbed and used."
🔸 Hydration and a good digestive system also help to eliminate this fatty mass.
🔸 Stress management is also important in gaining or losing fat mass."Stress leads to the secretion of cortisol, a hormone that disrupts lipid and protein metabolism and facilitates fat storage to the detriment of muscle synthesis", explains our specialist. .
🔸 Finally, sleep is the last factor that is all too often neglected."We know that people who do not sleep properly, do not lose weight as well as those who sleep efficiently and have an easier time storing fats and/or sugars from their food”. Read our advice on getting the right amount of sleep here.
"Everyone is different: Lifestyle, dieting history and age-related hormonal changes all influence fat gain and the ability to reduce it.Losing body fat is all about adopting a lifestyle, and therefore changing it.It's important to remember that everything is linked.If you eat more healthily and exercise regularly, you're bound to sleep better and have lower stress levels.This will make it easier for you to lose body fat", concludes our specialist. Patience and regularity are needed to bring about positive changes in FMI.
The fat mass index, its various methods of calculation, and the difference with the body mass index now hold no secrets for you.
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