Why Older Adults Lose Weight, and What to Do: Is “Simple Food Is Healthy” Still True in Later Life?

Written by: 稲山 未来 (Registered Dietitian)

Their weight had stayed the same for years, but as they’ve grown older, it has been slowly dropping. Have you ever seen someone like that? Or perhaps you have worried, “So-and-so down the street seems to have lost weight lately. I wonder if they’re eating properly.”

In this column, I’ll explain how weight loss harms the bodies of older people, why they lose weight, and what can be done about it.

The harm caused by weight loss

Research has found that about 10 to 20 percent of people aged 65 and over who live at home tend to be underweight.

A common guideline for being underweight is a BMI of 20 or below. BMI (body mass index) shows the balance between height and weight: a lower value indicates a tendency to be underweight, and a higher value a tendency toward obesity. To give a sense of BMI 20: for a person 160 cm (5 ft 3 in) tall, it corresponds to a weight of 51 kg (about 112 lb). In other words, a person who is 160 cm tall and weighs 51 kg or less is considered underweight.

BMI is calculated as weight (kg) ÷ height (m) ÷ height (m). Try checking your own balance.

Losing weight means the body is not getting enough nutrition. Because the person is not getting enough energy from meals to keep the body going, the body is producing energy by using up the fat and muscle it has stored.

As a result, the body is constantly undernourished, and the first thing to decline is immunity. The person becomes more prone to infections, so they catch colds more often, and aspiration pneumonia, which you often hear about, is more likely to become severe.

That’s not all. The longer undernutrition continues, the more the body draws energy from fat and muscle, so muscle mass declines. Moving around becomes a chore, and the person can no longer move quickly, which leads to more falls.

The throat structures we use to swallow food are also largely made of muscle. As the swallowing muscles weaken, the person coughs and chokes more often and may develop dysphagia, a disorder of swallowing.

So why do so many older people become undernourished?

Causes of weight loss and what to do

1. They want to eat but can’t

For example, when teeth are lost to cavities or gum disease and few healthy teeth remain, fibrous foods such as vegetables and chewy foods such as meat become hard to eat. The result is a situation of “I want to eat it, but it’s too hard.” The more foods become hard to eat, the more unbalanced the diet becomes, and the harder it is to get enough nutrition.

In that case, first get treatment at a dental clinic to restore the lost chewing function. Of course, prevention matters too, so regular dental checkups are a good idea.

That isn’t the only reason people can’t eat. When they have fewer chances to move or spend more time lying down, they naturally don’t feel hungry. But if they eat less as a result, their strength declines further and further until they can no longer move. This is a vicious circle, so try to stay active, even a little, while keeping up with meals.

People with eating and swallowing disorders (dysphagia), who have difficulty chewing and swallowing, are in exactly this situation: they want to eat, but their bodily functions can’t keep up. If they keep eating the same meals as before despite this decline, there is a risk of choking and aspiration.

If something feels wrong when eating, such as persistent coughing or a feeling that food gets stuck when swallowing, it is important to consult a dentist.

2. They think they’re eating, but they aren’t getting enough nutrition

When we don’t have much of an appetite, we tend to choose light foods that go down easily. But light foods often contain correspondingly little nutrition. For example, eating nothing but somen noodles when you have no appetite leads to an unbalanced diet. Simply switching from the usual noodle dipping sauce (mentsuyu) to a sesame sauce raises the calories, and topping the noodles with tuna or thin strips of omelet adds protein too.

Instead of assuming, “I’m full, so I must be getting enough nutrition,” think about how much nutrition you are actually getting.

3. They believe simple, plain food is good for the body

When we were young and in the prime of our working lives, we were told, “Overeating leads to obesity” and “Cut down on oily food, because it causes lifestyle diseases.” In fact, this way of thinking doesn’t always apply to older people.

That is because, with age, the digestive and absorptive functions that take nutrients into the body also decline. So rather than “You mustn’t eat oily food,” older people need to make good use of oil to take in energy efficiently.

Simply changing everyday simmered dishes and dressed vegetable dishes to stir-fries and salads with dressing raises the calories. When someone can’t eat large amounts, find ways to get plenty of calories from small amounts.

MCT oil (medium-chain triglyceride oil), which is less greasy and less likely to sit heavily in the stomach, is now also on sale, so why not give it a try?

It is also important to review how you get your nutrition, so that a habit of eating simply, which you kept up for your health, doesn’t lead to undernutrition as you age. If you have dietary restrictions because of diabetes, dyslipidemia or another condition, follow the instructions of your doctor or registered dietitian.

Take in nutrition efficiently to avoid losing weight

As explained above, for older people, losing weight and muscle brings many harms: the legs and lower back weaken and the range of activities narrows; immunity declines and infections become more likely; and the throat muscles weaken, leading to difficulty eating and swallowing.

In later life, losing weight is a greater health risk than gaining it.

First, take a fresh look at your eating habits and think carefully about why you are losing weight. And remember that muscle, once lost, is hard to regain. If you notice weight loss, take action early.

If you aren’t sure what to do, consult your family doctor or a registered dietitian.

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About the author: 稲山 未来 (Registered Dietitian)

This article is a contribution from a medical or care professional, re-edited by our editorial team. It provides general information as of the time of writing, and symptoms and circumstances differ from person to person. For specific decisions, please consult your doctor, dentist, pharmacist or another professional.

This is an English translation of a column originally published in Japanese by Next Co., Ltd.

About Next Co., Ltd. We are a Tokyo-based company working in Japan’s senior care and end-of-life planning field. Alongside these expert columns, we publish professional training textbooks and support businesses entering Japan’s eldercare market. More expert columns | Our English textbook | Contact us