What BMI for a 70-year-old woman?
In 2020, nearly one in two French people is overweight or obese. And this phenomenon does not spare seniors, since they are 19.2% among those aged 65 and over to display an abnormally high weight(1). Women in their seventies are not spared, overweight being one of the direct consequences of the metabolic slowdown related to their age. But should the weight of the elderly be estimated in the same way as that of young individuals? For a 70-year-old woman, what is a normal BMI?
What is BMI?
Body Mass Index (BMI) or Quetelet Index is acalculation used to estimate a person’s body size. It is calculated according to the height andbody massof an individual, according to the following formula: P/T2 (P being the weight in kg and T the height in meters). Thus, for a woman of 1.70 m and 58 kg, the BMI will be = 58 / 1.70 2 = 58 / 2.89 = 20.07 (20.02 kg / m2). Note that there areautomatic BMI calculators, ashere.
The interest of BMI is that it is agood basic indicatorto assess the “normality” of weight and thus, the potential risks associated with overweight. The World Health Organization interprets it as follows:
- BMI less than 16 – anorexia or undernutrition;
- BMI between 16.5 and 18.5 – thin;
- BMI between 18.5 and 25 – normal build;
- BMI between 25 and 30 – overweight;
- BMI between 30 and 35 – moderate obesity;
- BMI between 35 and 40 – high obesity;
- BMI over 40 – morbidor massive obesity.
What are the limits of BMI?
Despite being a relatively reliable indicator, BMI has some limitations.
First of all, it is only aimed atadults aged 18 to 65and makesno distinction between men and women. Thus, if you are a 70-year-old woman, the data may not be completely reliable and give a biased indication of body mass. This is the main criticism of the indicator.
physical activity (which can greatly vary body mass). Thus:
- a high-level athlete with dense muscle mass (therefore heavy) can display a high BMI, without being overweight or presenting health problems;
- a naturally stocky individual, provided with a solid frame, can display a high BMI but be in perfect health and, here again, absolutely not in a situation of overweight;
- a rather slender person, with a BMI within the norm, can on the contrary be endowed with a significant fat mass and at risk of developing a cardiovascular disease.
Finally, there is the case ofpregnant women, for whom BMI is not an appropriate measurement tool, as weight varies de facto throughoutpregnancy.
Case of women aged 70 and over: how to calculate their BMI?
From the age of 70, two things must be monitored in women:age-related undernutritionandobesity. What for? Simply because from this age, the risks associated withmetabolic slowdownare frequent. The latter is explained as follows:
- The 70-year-old woman ismenopausal, which inducesless hormonal activity ;
- (loss of muscle mass);
- feelings of hunger and satiety are sometimes altered;
- the assimilation of nutrients from food is less effective ( malabsorption );
To this are added other contributing factors : social and family isolation, sometimes declining mental health, taking medication, oral problems modifying the diet, financial difficulties…
Thus, the WHO has revised the BMI classification for people over 70 – male or female. It is broken down as follows(2)
- BMI less than 21 – undernutrition;
- BMI between 21 to 25 – normal build;
- BMI between 25 and 30 – overweight;
- BMI between 30 and 35 – moderate obesity ;
- BMI between 35 and 40 – high obesity;
- BMI over 40 – morbid or massive obesity.
What to do if the BMI of a 70-year-old woman is not within the norm?
The case of undernutrition
We speak of Undernutrition when the body has a Nutritional Imbalancetag. The diet does not provide enoughcarbohydrates , Protein, and/or other nutrients to function optimally. It translates, in a 70-year-old woman, into a BMI < 21.
The consequences :
- significant weight loss;
- a decrease in adipose tissue;
- loss of muscle mass;
- immune ;
- a general state of weakness;
- chilliness;
- an increased risk of bone fracture;
- disorders ;
- cognitive disorders;
- impaired quality of life…
What to do to remedy it? Most of the time, a change in diet is enough to restore the weight and return to a normal BMI. It is often advisable to enrich your food bowl with protein (to neutralize sarcopenia), at the rate of 30 g per day and to consume moreLean Dairy Products(to avoid osteoporosis and dental disease). The diet should also be rich in fruits and vegetables, providers ofantioxidantvitamins . If the preparation of the meals proves to be complicated, a solution to help or carry meals can be considered. Finally, daily movement should be maintained, as physical activity keeps muscle mass afloat and strengthens bones.
Case of overweight
On the other hand, it happens that from the age of 70, a woman tends to gain more weight than reason. The main cause of overweight (or even obesity) in seniors is the metabolic slowdown associated with inactivity. In these cases, the health risks consist of developing a cardiovascular pathology,metabolic syndrome , Diabetes , cancer, early mortality, Joint disorders , brain aging, etc.
The calculation of the BMI must be supplemented by other measurements: blood biology, estimation of adiposity, measurement of the waist circumference, measurement of the skin fold.
Finally, to find a BMI within the norm, in the event of overweight, the 70-year-old woman must:
- correct your diet, avoiding the consumption of sugar, saturated fats, processed dishes, alcohol, and continuing a sufficient consumption oflean proteins (vegetable or animal), fruits and vegetables, complex carbohydrates;
- Resume physical activity, no matter how small, through dailywalks, cycling, soft gym, or fun gardening activities.
Stephen Paul is the lead author and founder of My Health Sponsor. Holder of a diploma in health and well-being coaching with more than 200 articles in the field of health, he makes it a point of honor to offer advice based on reliable information, based on scientific research, and verified by health professionals.