A healthy weight for a 73-year-old woman typically falls in a higher range than you might expect. While standard guidelines define a “normal” BMI as 18.5 to 24.9, research on older adults consistently shows that a BMI of 25 to 27, technically in the “overweight” category, is associated with the best health outcomes after age 70. For a woman who is 5’4″, that translates to roughly 145 to 157 pounds. For a woman who is 5’6″, it’s about 155 to 167 pounds.
Why the “Ideal” Weight Shifts After 70
The BMI ranges designed for younger adults don’t map neatly onto older bodies. Studies have identified an increased risk of death in older adults when BMI drops below 23 or climbs above 33, which means the sweet spot is broader and shifted upward compared to the standard range. A BMI around 26 appears to offer a particularly good balance: it supports bone mineral density without significantly raising the risk of heart disease or diabetes.
Carrying a bit of extra weight serves a protective function as you age. Body weight puts mechanical stress on bones, which helps maintain their density. Research on people over 50 found that bone mineral density increases with BMI up to a saturation point of roughly 26 to 27, after which additional weight stops helping your bones and starts creating other problems. The National Institutes of Health specifically notes that a BMI of 25 to 27 may protect against osteoporosis, a major concern for postmenopausal women.
Weight Ranges by Height
Here’s what a BMI of 25 to 27 looks like in actual pounds, depending on your height:
- 5’0″: 128 to 138 lbs
- 5’2″: 137 to 148 lbs
- 5’4″: 145 to 157 lbs
- 5’6″: 155 to 167 lbs
- 5’8″: 164 to 177 lbs
- 5’10”: 174 to 188 lbs
These numbers are a starting point, not a prescription. Your frame size, muscle mass, and overall health matter more than hitting a specific number on the scale.
The Risks of Weighing Too Little
For older women, being underweight is often more dangerous than being slightly overweight. Underweight women have the highest fracture rates among postmenopausal women. A hip fracture after 70 can trigger a cascade of complications: hospitalization, immobility, muscle loss, and infections. Low body weight also means less cushioning around the hips, which makes falls more damaging.
Unintentional weight loss is especially concerning. Losing weight without trying can accelerate muscle wasting, a condition called sarcopenia that affects a significant number of people over 70. When you lose weight without resistance exercise, your body breaks down muscle along with fat. The result is that you may weigh less but actually become weaker and more fragile. If you’ve noticed your weight dropping without changes to your diet or activity, that’s worth investigating.
Why the Scale Doesn’t Tell the Whole Story
Two women who are the same height and weight can have very different health profiles depending on where they carry their weight and how much of it is muscle versus fat. As you age, your body naturally shifts its composition: muscle decreases and fat increases, even if the number on the scale stays the same. This means a 73-year-old woman might weigh exactly what she did at 50 but have significantly less muscle and more body fat.
Sarcopenic obesity is the term for this combination of low muscle mass and high body fat. It raises health risks more than either condition alone. The key insight: your weight can look “normal” while your body composition is actually problematic. Strength and function matter more than the number on the scale.
Waist circumference is a more useful measure of metabolic risk than BMI alone. The American Heart Association notes that women with a waist measurement greater than 35 inches face higher risk of heart disease and type 2 diabetes. Waist size predicts heart attacks better than BMI does, especially in women. You can measure yours by wrapping a tape measure around your midsection at the level of your belly button.
Keeping Your Weight Stable and Healthy
For most women in their 70s, the goal isn’t weight loss. It’s maintaining a stable weight while preserving muscle mass. That takes two things: adequate protein and regular resistance exercise.
Researchers recommend that older adults consume 1 to 1.2 grams of protein per kilogram of body weight each day. For a 155-pound woman, that works out to about 70 to 85 grams of protein daily, which is notably higher than what many older adults actually eat. Spreading protein across all three meals (rather than loading it into dinner) helps your body use it more effectively for muscle repair.
Calorie needs depend on how active you are. The National Institute on Aging estimates that women over 60 need about 1,600 calories per day if they’re not physically active, 1,800 if moderately active, and 2,000 to 2,200 if they maintain an active lifestyle. Eating too few calories makes it nearly impossible to get enough protein and nutrients to maintain muscle and bone.
Strength training is the other half of the equation. Weight-bearing and resistance exercises directly counter sarcopenia by stimulating muscle growth and helping bones stay dense. Even bodyweight exercises like squats, wall push-ups, and standing on one leg make a measurable difference. Without regular resistance exercise, intentional or unintentional weight loss tends to strip away muscle along with fat, leaving you lighter but more vulnerable to falls and fractures.