Mediterranean Diet, Weight Loss, and Cognition in Obese Older Adults
Condition: Cognition; Obese Older Adults; Mediterranean Diet
MeSH terms: Weight Loss
Study type: Interventional

Summary: 
      The deleterious effects of obesity on cardiovascular disease (CVD) and metabolic risk factors
      (dyslipidemia, hypertension, and insulin resistance) are well-documented. Recent evidence
      also links obesity to cognitive decline and dementia. Dietary patterns are central to the
      development and maintenance of obesity and certain dietary patterns may contribute to the
      onset and progression of cognitive decline. With the rapid aging of the US population and the
      high prevalence of obesity among older adults, innovative lifestyle strategies to prevent
      cognitive decline among ethnically diverse obese older adults are critically needed.
    

Detailed description: 
      Obesity is a leading cause of death and disability in the United States, affecting as many as
      80 million Americans. It is well-established that obesity contributes to a number of risk
      factors for metabolic abnormalities and cardiovascular diseases (CVD), including
      hypertension, diabetes, and hyperlipidemia. In addition, there is growing evidence that
      obesity is associated with cognitive deficits in multiple domains, even in otherwise healthy
      older adults. With the rapidly aging US population and the high prevalence of obesity among
      older adults, innovative strategies to prevent cognitive decline in this population are
      needed. Dietary patterns are central to the development and maintenance of obesity and
      evidence suggests that dietary factors also may affect cognition. Studies have shown that
      adherence to a Mediterranean Diet (MedDiet) is associated with less cognitive decline and
      reduced risk for dementia in older adults. Weight loss through caloric restriction also has
      been shown to improve cognitive function in obese adults. Both the MedDiet and weight loss
      are thought to improve cognition in obese individuals and reduce CVD/metabolic risk through
      beneficial changes in systemic inflammation and oxidative stress. The identification of
      effective lifestyle interventions for diet/weight management to improve cognition among obese
      older adults is a public health priority. However, no randomized controlled trials (RCTs)
      have examined the effect of the MedDiet with and without caloric restriction, to promote
      weight loss on cognitive functioning in obese older adults. The investigators propose a
      three-arm RCT in which 180 obese (body mass index [BMI] ≥ 30 and < 50 kg/m²) older adults
      (55-80 years) will be randomized to: 1) an 8-month MedDiet Alone, without caloric
      restriction/weight loss (MedDiet-A); 2) an 8-month MedDiet lifestyle intervention with
      caloric restriction/weight loss (MedDiet-WL); or 3) an 8-month typical diet control (TDC)
      without caloric restriction/weight loss. The investigators will test the following
      hypotheses: 1) participants randomized to MedDiet-A and MedDiet-WL will achieve greater
      improvements in cognition compared to participants randomized to TDC; 2) participants
      randomized to MedDiet-WL will exhibit greater improvements in cognition compared to
      participants randomized to MedDiet-A; 3) participants randomized to MedDiet-A and MedDiet-WL
      will show greater improvements in CVD/metabolic risk factors, systemic inflammation,
      OxStress, and body weight/composition compared to participants in TDC; 4) participants
      randomized to MedDiet-WL will exhibit greater improvements in CVD/metabolic risk factors,
      systemic inflammation, OxStress, and body weight/composition compared to MedDiet-A; 5)
      improvements in CVD/metabolic risk factors, body composition, systemic inflammation, and
      OxStress will mediate the relationship between MedDiet and improved cognition. The
      investigators also will determine the extent to which changes in dietary habits, weight and
      cognitive functioning are maintained over a 6-month follow-up period.
    

Intervention name(s): MedDiet
Intervention type(s): Behavioral
Intervention description(s): Research subjects will be randomly assigned to one of three intervention groups.
The MedDiet-A group will learn about and how to adhere to the Mediterranean Diet. Over the course of 8 months, they will receive twenty-two classes 60-minute in length.
The MedDiet-WL group will learn about the Mediterranean Diet, how to adhere to is and engage in lifestyle choices like exercising and eating fewer calories so that they will loose weight. Over the course of 8 months they will receive 22 classes, each 90 minutes in length.
The Typical Diet Control group will be asked to maintain current eating and activity patterns over the course of the 14 month study.
Allocation: Randomized
Intervention model: Parallel Assignment
Masking: Single (Participant)
Primary purpose: Other