Association of personalized dietary advice aiming to increase protein intake with macronutrient intake of community-dwelling older adults: a secondary analysis of the PROMISS RCT.

Purpose: The PROMISS randomized-controlled trial (RCT) showed that personalized dietary advice, regarding, for instance, protein-enriched food products, increased protein intake among community-dwelling older adults with a low habitual protein intake. This secondary analysis evaluates how the dietary advice aimed solely at increasing protein intake affects the intake of other (macro)nutrients, saturated fat, sugars, and dietary fiber.

Methods: Community-dwelling older adults (n = 260, mean age 75 years, 53% women) in Finland and the Netherlands with a habitual protein intake < 1.0 g/kg adjusted body weight/day were included in this secondary analysis. The two intervention groups (n = 175) received personalized dietary advice for 6 months to increase protein intake. The control group (n = 85) received no intervention. Nutrient intake was evaluated with 24 h recalls and a 3-day food record at baseline and follow-up.

Results: Macronutrient intake at baseline was similar across groups. In addition to an increase in protein, the intervention groups showed a significant increase in carbohydrate intake relative to the control group, with no change in the intake of total fat, saturated fat, sugars, or dietary fiber. An increase in energy intake was associated with an increase in protein intake [r = .55 (95% CI 0.46-0.63)] but not with relative weight gain [r = 0.03 (95% CI - 0.09 to 0.16)].

Conclusion: Dietary advice to increase protein intake increased also the intake of carbohydrates, but intakes of fiber, sugars, and (saturated) fat remained at baseline levels.