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Page 14 of 35 Boyajian et al. Microbiome Res Rep 2024;3:29 https://dx.doi.org/10.20517/mrr.2024.05

microbiome in overweight or obese individuals, according to recent clinical trials [120,121] . A narrative review
by Chao et al. further discusses dietary interventions for obesity and their potential mechanisms
[117]
contributing to weight loss and dietary adherence . Behavioral counseling interventions to enhance
adherence to prescribed meal plans and increased physical activity are also recommended by experts, as
dietary adherence is reportedly the most powerful predictor of weight loss success . Cognitive behavioral
[115]
therapy is one method that can be implemented alongside lifestyle modifications to help manage patient
goals and address unhealthy behaviors, such as emotional eating . Although behavioral modifications are
[122]
recommended as first-line therapy for obesity, they often fail to achieve sustained weight loss. A meta-
analysis of 27 clinical trials on obese individuals receiving nutritional weight loss interventions revealed that
continuous weight gain occurs 9 months after intervention conclusion, with some patients returning to
[123]
their baseline weight before one year . Weight loss-induced physiological changes such as adaptive
processes that work to prevent starvation mode , changes in adipocyte size and function , or
[124]
[125]
inflammation from metabolic adaptation are possible mechanisms driving weight regain in obese
individuals after behavior-induced weight loss .
[126]
Lifestyle choices can be modified to achieve healthy aging and prolong lifespan. A clinical trial on healthy,
biologically aging adult males (aged 50-72) successfully decreased epigenetic age by 3.23 years after 8 weeks
of interventional diet (i.e., high-nutrient and plant-centered diet with fruit/vegetable powder and probiotic
supplements) and lifestyle (i.e., 30 min of exercise at least 5 days/week, breathing exercises and a minimum
[127]
of 7 hours of sleep) . Like obesity, caloric restriction (e.g., 25% caloric intake) can improve aging by
[128]
slowing or reversing the related molecular changes . Metabolism can also be modulated by periodic
fasting, which induces ketogenesis and increases mitochondrial DNA. Lilja et al. demonstrated longevity-
associated changes to the gut microbiota (e.g., increased abundance of Christensenella) and increased
expression of Sirt1 in overweight adults (aged 23-75; average BMI of 25.93 kg/m ), following five days of
2
periodic fasting . Dietary interventions for physical and cognitive decline have also been studied in aged
[129]
persons, namely the Dietary Approaches to Stop Hypertension (DASH) diet and the Mediterranean-DASH
Intervention for Neurodegenerative Delay (MIND) diet . These specific diets are rich in omega-3 fatty
[130]
acids, antioxidants, and polyphenols, exerting anti-inflammatory and neuroprotective benefits. Studies of
the DASH diet report significant reductions in blood pressure and an increased effect correlated with
sodium intake compared to a normal diet, although the impact on elder individuals is less than on younger
individuals . Moreover, a combination of the MIND diet and aerobic exercise further improves cognitive
[131]
function in obese elderly women and may substitute for sex hormone deficiency in postmenopausal
women . A long-term study of the MIND diet on brain function in overweight elders at risk for dementia
[132]
is ongoing and may provide mechanistic evidence of the diet’s effects . However, aging individuals may
[133]
face societal and health service obstacles when modifying their lifestyles. Toward this end, governmental
policies have been recommended by the WHO to designate the period from 2020 to 2030 as the “Decade of
Healthy Ageing” . The policies regard global data collection on the health status of older people,
[8]
conducting research on healthy aging, increasing accessibility to healthcare, and establishing integrated
long-term care services. Other efforts to reduce age discrimination and provide age-friendly cities and
communities are also discussed. Similarly, the UK government recently released a consensus statement on
healthy aging, which includes a discussion on preventative healthcare, opportunities for older adults to
contribute to society, and the promotion of active and independent lifestyles . Such policies will help
[134]
create environments and promote behavior that fosters healthy aging, similar to what is implemented in
blue zone populations [135,136] . Societal efforts to improve the lifestyle of elder individuals are encouraging and
imperative for the rising aging population.