Is Weight Gain a Symptom of Alzheimer’s Disease?

Weight gain is not typically considered a core symptom of Alzheimer’s disease. Most research and clinical experience suggest that weight loss is more common as Alzheimer’s progresses, and it can even begin years before noticeable memory problems. ^{[1] [2]} In early stages like mild cognitive impairment (MCI), changes in weight can occur, but overall, Alzheimer’s is more consistently linked with involuntary weight loss rather than weight gain. ^{[3] [2]}

---

What Usually Happens to Weight in Alzheimer’s?

• Weight loss is common and can be persistent over time. In longitudinal observations, over 70% of people with Alzheimer’s lost weight, and the rate of loss exceeded that seen in age-matched controls. ^[1] In outpatient cohorts, nearly all individuals with Alzheimer’s lost weight over one year, even though some reported eating more. ^[4]
• Weight loss may precede symptoms. There is evidence that losing weight can occur years before cognitive decline becomes obvious, suggesting complex biological links between metabolism, appetite control, and brain changes. ^[2]

---

Why Does Weight Loss Occur?

Weight loss in Alzheimer’s appears to be multifactorial:

• Reduced intake: Difficulty with planning, remembering to eat, or coordinating eating can lead to lower calorie intake. ^[2]
• Behavioral changes: Restlessness, wandering, or agitation can increase energy expenditure and reduce time spent eating. ^{[5] [2]}
• Metabolic factors: Some studies have raised the possibility of a hypermetabolic state, where the body burns more energy despite adequate food intake, although this is not fully confirmed in humans. ^{[4] [2]}
• Brain regions for appetite: Alzheimer’s-related neurodegeneration affects areas responsible for hunger, satiety, and food preference, contributing to altered eating patterns. ^[2]

---

Can Weight Gain Happen in Alzheimer’s?

While weight loss is more typical, weight gain can occur, but it is usually due to secondary factors rather than the disease process itself:

• Medications: Some drugs used to manage behavioral symptoms such as certain antipsychotics (e.g., olanzapine, quetiapine, brexpiprazole) and some antidepressants are known to increase appetite and cause weight gain in many people. ^{[6] [7] [8]}
• Reduced physical activity: As functional abilities decline, less movement can lead to weight gain in some individuals, especially if calorie intake remains high. ^[9]
• Dietary changes: Care strategies that introduce calorie-dense foods or sweet preferences can increase intake and weight in a subset of people.
• Comorbid conditions: Hypothyroidism, edema, or steroid use can cause weight gain and may coexist with Alzheimer’s.

Importantly, controlled studies of disease progression show that in early-stage Alzheimer’s, differences by BMI or short-term weight change are not consistent, while in amnestic MCI, weight loss may be associated with faster progression and higher BMI with slower progression. ^[3] This pattern underscores that weight gain is not a hallmark symptom of Alzheimer’s itself. ^[3]

---

Practical Implications for Care

• Monitor weight regularly: Routine tracking helps identify trends early; both unintentional loss or gain warrant attention. ^[2]
• Review medications: If significant weight gain occurs, discuss whether any psychotropic medications may be contributing and whether alternatives or dose adjustments are appropriate. ^{[8] [6] [7]}
• Assess diet and activity: Aim for balanced nutrition (adequate protein, fiber, and micronutrients) and safe, tailored physical activity to maintain healthy weight and overall function. ^[9]
• Screen for medical causes: Evaluate thyroid function, fluid status, and other conditions that can drive weight changes.
• Support eating behaviors: Structured mealtimes, simple foods, cueing, and caregiver support can reduce weight loss risk and improve intake quality. ^[2]

---

Summary Table: Weight Patterns and Drivers in Alzheimer’s

Aspect	Typical Direction	Common Drivers	Notes
Alzheimer’s disease itself	Weight loss	Lower intake, behavioral energy expenditure, appetite regulation changes, possible hypermetabolism	Weight loss may begin before cognitive symptoms; frequent across stages. [1] [4] [2]
Early-stage (MCI)	Mixed; weight loss linked to faster progression	Nutritional risk, activity changes	Higher BMI may be associated with slower clinical progression in MCI. [3]
Medication-related	Weight gain	Antipsychotics, some antidepressants	Consider medication review if gain is significant. [6] [7] [8]
Lifestyle/comorbidities	Either gain or loss	Physical inactivity, diabetes, thyroid disease	Cardiometabolic factors influence dementia risk and weight. [9]

---

Key Takeaway

Weight gain is not a typical symptom of Alzheimer’s disease, and if it occurs, it often reflects medication effects, reduced activity, or other health issues rather than the disease itself. ^{[1] [2]} Weight loss is more consistently observed across Alzheimer’s stages, sometimes even before memory symptoms, and deserves proactive nutritional and medical management. ^{[4] [2]}