09 November 2022
4 minutes of reading
HoustonDK. Calorie restriction and older adults: what we know and don’t know about diet, longevity, and aging. Presented at: Obesity Week; November 1-4, 2022; San Diego.
Houston does not report relevant financial disclosures.
SAN DIEGO — Weight loss through calorie restriction can improve cardiometabolic risk, chronic conditions and physical function for older adults with obesitybut certain factors must be considered when designing an intervention.
During a presentation at ObesityWeek 2022, Denise K. Houston, PhD, RD, professor of gerontology and geriatric medicine at Wake Forest University School of Medicine, discussed how losing weight later in life can exacerbate age-related declines in lean mass and bone mineral density. Houston said that consuming more protein and calcium in a calorie restricted dietalong with exercise, it can help mitigate this loss of lean mass and BMD.
“We need to think about how we might adapt these weight loss recommendations for older adults,” Houston said. “We know that risk factors for weight-related diseases lose predictive power in old age. The clinical setting is markedly different in older adults, they have many different chronic conditions, are taking many different medications, and may be frail. The value of disease and mortality may not be the same in older adults, as they may place more value on physical and cognitive function, as well as quality of life. And we know that the trajectory of weight, as well as the trajectory of body composition, is different in older adults.”
Pros and Cons of Weight Loss for Seniors
A 2005 position statement from the American Society for Nutrition and the Obesity Society, as well as the 2013 guidelines for the management of obesity from the American Heart Association, the American College of Cardiology, and the Obesity Society, describe weight loss interventions for older adults as “controversial” due to reductions in relative health risks associated with increased BMI in old age; uncertainty about how well obesity treatments work; a lack of evidence on the effect of weight loss on cardiovascular disease, longevity, and risk of osteoporosis; and possible harmful effects related to loss of muscle and bone mass.
“When we think about older adults and the association between BMI and mortality, what we see is that the low point of BMI changes to a higher BMI as age increases,” Houston said. “Older adults tend to have the lowest mortality risk in the overweight range, which is different from younger and middle-aged adults.”
Several studies have found that weight loss in older adults is associated with an increased risk of mortality, Houston said. In a meta-analysis published in scientific reports in 2018, adults who lost weight unintentionally had a higher risk of mortality compared to those who lost weight intentionally (HR, 1.38; 95% CI, 1.23-1.53). Mortality risk was even higher in studies that focused on adults aged 65 years and older (HR = 1.81; 95% CI, 1.59-2.03). In addition, data from the Cardiovascular Health Study in adults 65 years and older showed that greater weight variability and cycling from weight loss to weight gain were associated with increased risks of impaired mobility, disability, and mortality.
Despite those findings, there has been evidence showing that calorie restriction and physical activity may be beneficial for older adults with obesity, Houston said. In the Look AHEAD trial findings, participants randomized to a lifestyle intervention maintained improvements in physical function over 10 years, despite regaining weight lost in the first year of the trial. The lifestyle intervention was also associated with faster walking speed and better physical performance 11 years after randomization. Furthermore, in a meta-analysis published in IT ISEITHERSOnortheast in 2015, middle-aged and older adults who consumed a calorie-restricted diet had a lower risk of mortality than those who did not engage in calorie restriction (RR = 0.85; 95% CI, 0.73-1).
Houston said there are downsides to weight loss for older adults. Calorie restriction can lead to nutrient deficiency, worsen age-related losses in strength, lean mass, and BMD, and increase the risk of fractures. In the Look AHEAD trial, adults in the lifestyle intervention group had a higher risk of fragility fractures than those in the control group (HR = 1.39; 95% CI, 1.02-1, 89).
Mitigation of lean mass loss, BMD
To combat these negative effects, older adults with obesity may want to consume more protein and calcium during calorie restriction, Houston said. In a meta-analysis published in Nutrition Reviews in 2016, middle-aged and older adults who ate more protein during calorie restriction lost more fat mass and retained more lean mass than adults who ate less protein. In another study published in The Journal of Bone and Mineral Research in 2005, postmenopausal women consuming a calorie-restricted diet had attenuated bone loss with 200 mg or 1,000 mg per day of calcium supplementation.
Physical activity is also beneficial for older adults trying to lose weight. In a study published in The New England Journal of Medicineolder adults who participated in calorie restriction had lower lean mass losses and BMD if they participated in resistance training or a combination of aerobic and resistance training.
More protein and calcium combined with exercise may help attenuate lean mass loss and BMD, but weight regain may not have the same beneficial effect. A study published in Tthe American journal of clinical nutrition in 2011 showed that people lose more lean mass during weight loss than they gain during weight regain. Another study published in 2011 in Obesity found that BMD does not recover during weight regain after weight loss. Houston said that while losing weight might be beneficial for older adults, regaining the weight could lead to worse outcomes for older adults than younger adults who regain the weight after losing it.
More weight-loss interventions that target fat mass while preserving lean mass and bone are needed, he said. Also, more research needs to be done to examine whether the health benefits of prior weight loss persist after weight regain.
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