Mother was wrong — it turns out that you can be too thin
Those reassuring maxims our mothers told us endure because they seem to reflect some truth, don’t they?
“You can never be too rich or too thin” was one I oft heard.
I tried to find a rich man. But they were few and far between and they seemed to generally ignore their mothers’ saying, “beauty is only skin deep.”
So my marital pick and I entered our partnership in about the same financial straights.
On the other hand, I turned out thin, an outcome most women pursue determinedly over a lifetime. Yet, most adult Americans today are overweight or obese.
Now the shocker: Our moms got this one (at least partly) wrong. As we age, being too thin is likely bad for us — as bad as obesity. Overweight (not obesity) in elders, from a purely health perspective, seems perfectly OK.
In fact, what is really bad at older ages (say in our 70s and 80s) is weight loss.
Large prospective studies following adults over periods of decades show that weight or body mass index (BMI: weight for a given height) versus health forms a J-shaped curve. Too little (BMI <18.5) or too much (BMI>30) is associated with both disability and earlier death.
Debatable is which is the chicken and which the egg. Is low weight/weight loss causing health declines? Or are unrecognized health declines causing morbidity and mortality?
What is not debatable is that obesity predicts disability and death and that the longer a person is obese, the greater these ill effects. Weight loss, particularly unintended, should be explored medically.
Also not debatable is that when pounds go, more of what is lost is
muscle mass. And if the weight is gained back, what is gained is mostly fat. It was long thought that low muscle mass, itself, is a predictor of morbidity, but that has not panned out — it is really a decline in muscle that leads to frailty.
Frailty is not a state to which anyone aspires.
In fact, counting age has become less meaningful to most of us than counting years of robustness. Oddly, despite its import, scientists do not fully agree on the definition of frailty. Geriatricians generally define frailty as “a biologic syndrome of decreased reserve and resistance to stressors, resulting from cumulative decline across multiple physiologic systems, and causing vulnerability to adverse outcomes.”
But different measures are used in various studies. The best for predicting the ability to carry-out activities of daily living, according to a recent systematic review are: unintentional weight loss, slow walking speed, low grip strength and low physical activity. A person with none of the indicators is defined as robust, one or two indicators makes us prefrail, and three or more tips us into being frail.
Frailty seems to be one of those terrible and inevitable consequences of getting very old. Again, this received wisdom may be (at least partly) wrong. A couple of clinical trials in pre-frail, 70+ year olds showed that multi-modal physical training centered on balance, muscle strength and mobilityimproved measures of frailty. Exercise programs that focused on just one type of training did not achieve the same success. Similarly, diet programs have not demonstrated great worth.
A friend’s mother worked out three times a week with her son, a professional trainer. She did squats, lifted weights, stood on one leg and walked. At the age of 99, she fell and only then became frail, dying within six months. Until then, she had lived an active, independent life.
So what should our mothers have told us?
Surely one message is that multi-modal physical activity should be maintained forever. The less obvious message should have been that being a bit hefty is not so terrible.
Frailty seems to be one of those terrible and inevitable consequences of getting very old.