Caloric restriction interventions may need to be adjusted for older adults with obesity
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SAN DIEGO — Weight loss through caloric restriction can improve cardiometabolic risk, chronic conditions and physical function for older adults with obesity, but certain factors should be considered when designing an intervention.
During a presentation at ObesityWeek 2022, Denise K. Houston, PhD, RD, professor of gerontology and geriatric medicine at the Wake Forest University School of Medicine, discussed how losing weight later in life can exacerbate age-related reductions in lean mass and bone mineral density. Houston said consuming more protein and calcium in a caloric-restricted diet, coupled with exercise, may help to 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 weight-related disease risk factors lose predictive power in older age. The clinical context is markedly different in older adults, they have many different chronic conditions, they’re taking many different medications and they may be frail. The value of disease and mortality may not be the same in older adults, as they may put more value into physical and cognitive function as well as quality of life. And we know the weight trajectory as well as the body composition trajectory is different in older adults.”
Pros and cons of weight loss for older adults
A 2005 position statement from the American Society for Nutrition and The Obesity Society, as well as a 2013 guidelines for managing obesity from the American Heart Association, American College of Cardiology and The Obesity Society, both describe weight-loss interventions for older adults as “controversial” due to reductions in relative health risks associated with increasing BMI in older age; uncertainty with how well obesity treatments work; a lack of evidence on the effect of weight loss on cardiovascular disease, longevity and osteoporosis risk; and potential harmful effects related to the loss of muscle and bone mass.
“When we think of older adults and the association between BMI and mortality, what we see is the nadir for BMI shifts to a higher BMI as we increase in age,” Houston said. “Older adults tend to have the lowest risk for mortality 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 for mortality, Houston said. In a meta-analysis published in Scientific Reports in 2018, adults who unintentionally lost weight had an increased risk for mortality compared with those who intentionally lose weight (HR = 1.38; 95% CI, 1.23-1.53). The risk for mortality was even greater 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 on adults aged 65 years and older showed that greater weight variability and cycling from weight loss to weight gain was associated with higher risks for mobility difficulty, disability and mortality.
Despite those findings, there has been evidence showing that caloric restriction and physical activity can be beneficial for older adults with obesity, Houston said. In findings from the Look AHEAD trial, participants randomly assigned to lifestyle intervention maintained improvements in physical function over 10 years, despite regaining weight that was lost in the first year of the trial. Lifestyle intervention was also associated with faster gait speed and better physical performance 11 years after randomization. Additionally, in a meta-analysis published in PLOS ONE in 2015, middle-aged and older adults who ate a caloric-restricted diet had a lower risk for mortality than those who did not engage in caloric restriction (RR = 0.85; 95% CI, 0.73-1).
Houston said there are downsides to weight loss for older adults. Caloric restriction may lead to a deficiency in nutrients, worsen age-related losses in strength, lean mass and BMD, and increase the risk for fractures. In the Look AHEAD trial, adults in the lifestyle intervention group had a greater risk for frailty fractures than those in the control group (HR = 1.39; 95% CI, 1.02-1.89).
Mitigating loss in lean mass, BMD
To combat these negative effects, older adults with obesity may want to consume more protein and calcium during caloric restriction, Houston said. In a meta-analysis published in Nutrition Reviews in 2016, middle-aged and older adults eating more protein during caloric restriction lost more fat mass while retaining 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 who consumed a caloric restriction 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 Medicine, older adults participating in caloric restriction had lower losses in lean mass and BMD if they participated in resistance training or a combination of aerobic and resistance training.
More protein and calcium combined with exercise can help attenuate the loss of lean mass and BMD, but weight regain may not have the same beneficial effect. A study published in The American Journal of Clinical Nutrition in 2011 showed people lose more lean mass during weight loss than what they gain during weight regain. Another study published in 2011 in Obesity found BMD does not rebound during weight regain after weight loss. Houston said that while losing weight might be beneficial for older adults, weight regain may lead to worse outcomes for older adults than younger adults who regain weight following weight loss.
More weight-loss interventions are needed that target fat mass while preserving lean mass and bone, she said. Additionally, more research should be done to examine whether the health benefits of previous weight loss persist after weight regain.
References:
- Beavers KM, et al. Am J Clin Nutr. 2011;doi:10.3945/ajcn.110.004895.
- De Stefani FDC, et al. Sci Rep. 2018;doi:10.1038/s41598-018-33563-z.
- Houston DK, et al. Obesity. 2015;doi:10.1002/oby.20944.
- Kim JE, et al. Nutr Rev. 2016;doi:10.1093/nutrit/nuv065.
- Kritchevsky SB, et al. PLoS One. 2015;doi:10.1371/journal.pone.0121993.
- Riedt CS, et al. J Bone Miner Res. 2005;doi:10.1359/JBMR.041132.
- Villalon KL, et al. Obesity. 2011;doi:10.1038/oby.2011.263.
- Villareal DT, et al. N Engl J Med. 2017;doi:10.1056/NEJMoa1616338.
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Houston DK. Caloric restriction and older adults: What we do and don't know about diet, longevity, and aging. Presented at: ObesityWeek; Nov. 1-4, 2022; San Diego.
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