Nutrient adequacy during weight loss interventions: a randomized study in women comparing the dietary intake in a meal replacement group with a traditional food group

BACKGROUND: Safe and effective weight control strategies are needed to stem the current obesity epidemic. The objective of this one-year study was to document and compare the macronutrient and micronutrient levels in the foods chosen by women following two different weight reduction interventions. METHODS: Ninety-six generally healthy overweight or obese women (ages 25–50 years; BMI 25–35 kg/m(2)) were randomized into a Traditional Food group (TFG) or a Meal Replacement Group (MRG) incorporating 1–2 meal replacement drinks or bars per day. Both groups had an energy-restricted goal of 5400 kJ/day. Dietary intake data was obtained using 3-Day Food records kept by the subjects at baseline, 6 months and one-year. For more uniform comparisons between groups, each diet intervention consisted of 18 small group sessions led by the same Registered Dietitian. RESULTS: Weight loss for the 73% (n = 70) completing this one-year study was not significantly different between the groups, but was significantly different (p ≤ .05) within each group with a mean (± standard deviation) weight loss of -6.1 ± 6.7 kg (TFG, n = 35) vs -5.0 ± 4.9 kg (MRG, n = 35). Both groups had macronutrient (Carbohydrate:Protein:Fat) ratios that were within the ranges recommended (50:19:31, TFG vs 55:16:29, MRG). Their reported reduced energy intake was similar (5729 ± 1424 kJ, TFG vs 5993 ± 2016 kJ, MRG). There was an improved dietary intake pattern in both groups as indicated by decreased intake of saturated fat (≤ 10%), cholesterol (<200 mg/day), and sodium (< 2400 mg/day), with increased total servings/day of fruits and vegetables (4.0 ± 2.2, TFG vs 4.6 ± 3.2, MRG). However, the TFG had a significantly lower dietary intake of several vitamins and minerals compared to the MRG and was at greater risk for inadequate intake. CONCLUSION: In this one-year university-based intervention, both dietitian-led groups successfully lost weight while improving overall dietary adequacy. The group incorporating fortified meal replacements tended to have a more adequate essential nutrient intake compared to the group following a more traditional food group diet. This study supports the need to incorporate fortified foods and/or dietary supplements while following an energy-restricted diet for weight loss.