Unexplained weight loss in older adults is something we need to take seriously.
In our weight-focused culture, it can be easy to assume that seeing the number on the scale go down is always a good thing. But when an older adult is losing weight without trying, we need to pay attention and figure out what is happening.
In this episode of The Geriatric Dietitian Podcast, we’re continuing our five-part series on BMI in older adults and talking about why unintended weight loss matters, when weight loss becomes concerning, and why protecting muscle is so important for healthy aging.
Why Unintentional Weight Loss Matters
When an older adult loses weight unintentionally, they can lose muscle along with that weight.
Muscle is incredibly important for healthy aging and independence. Loss of muscle can make everyday activities more difficult and is associated with falls, hospitalization, loss of independence, and increased mortality risk.
Rather than focusing only on whether someone’s BMI falls into a specific category, I want to know:
- What is their usual body weight?
- Is their weight stable?
- Has there been a sudden drop in weight?
- Has their weight slowly declined over the past six months or year?
- How are they eating?
- How are they moving their body?
- What is happening with their overall health?
Looking at changes over time can tell us much more than focusing on one number.
When Is Weight Loss Concerning?
Healthcare professionals use criteria for identifying significant unintended weight loss.
Significant weight loss is defined as:
- 5% of body weight in 30 days
- 7.5% of body weight in 90 days
- 10% of body weight in 180 days
But these numbers aren’t a reason to ignore weight loss until someone reaches one of those percentages.
Gradual, or insidious, weight loss can also be concerning. Someone may lose a few pounds here and there and eventually realize their weight has changed substantially. This is another reason knowing someone’s usual body weight and watching trends over time can be so valuable.
If unexplained weight loss is happening, we want to determine why.
Someone may simply be eating less, but there may also be an underlying medical condition, medication affecting appetite, or another reason that needs to be addressed.
Weight Loss and Muscle
Research discussed in this episode has connected weight loss in older adults with increased mortality risk. But one of the key things I want to come back to is muscle. When weight loss is happening unintentionally, muscle is likely being lost along with it.
This is why we don’t want to simply say, “They’re getting older. Of course they’re losing weight.”
We want to ask why. We want to identify what is happening and protect muscle and nutrition status.
Unintentional Weight Loss and Malnutrition
Unintended weight loss can also be connected with malnutrition.
In simple terms, malnutrition happens when someone isn’t getting the nutrition they need. This can lead to changes in body composition, including loss of muscle and fat, and can contribute to loss of independence.
Registered dietitians and other health professionals use screening tools to identify nutrition risk. One tool we use is the Mini Nutritional Assessment, or MNA.
The MNA looks at areas including:
- Decline in food intake
- Weight loss
- Mobility
- Psychological stress or acute disease
- Neuropsychological problems
- BMI
If someone screens as being at risk for malnutrition, ideally they should be referred to a registered dietitian.
Looking Beyond BMI
Dietitians can also assess nutrition status using a Nutrition Focused Physical Exam.
We look at things such as:
- Muscle loss
- Loss of subcutaneous fat
- Fluid accumulation
- Grip strength
This is another example of why BMI alone doesn’t tell us everything we need to know.
Ultimately, we care about what is happening in someone’s body, their ability to function, their health, and their quality of life. We aren’t simply focused on a number on the scale or a BMI chart.
When Weighing May Not Be Appropriate
Monitoring weight can be helpful for identifying unintended weight loss, but weighing isn’t appropriate in every situation.
For example, weighing may need to be reconsidered if someone:
- Has a history of eating disorders and weighing is triggering
- Is at high risk for falling while getting on a scale
- Is receiving hospice care
- Simply chooses not to be weighed
When it is appropriate and safe, monitoring weight can help us notice changes and identify unintended weight loss sooner.
What I Want You to Remember
When it comes to body weight in older adults:
- Know the person’s usual body weight
- Pay attention to changes over time
- Don’t automatically celebrate unintended weight loss
- Get to the root of why weight loss is happening
- Watch for changes in strength, muscle, nutrition, and function
- Prioritize weight stability and preserving muscle
If an older adult is losing weight without trying, don’t ignore it. We need to figure out what is happening and intervene. Weight stability and preserving muscle are what really matter.
In the next episode, we’re wrapping up our five-part BMI series and flipping the conversation around. We’ll talk about what older adults should consider when they intentionally want or need to lose weight.
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