Low-carbohydrate (LC) weight-reducing diets are popular choices for self-dieters. Eighteen adults (BMI >/= 25 kg/m(2)) were enrolled in this short-term longitudinal study to evaluate dietary intake and weight on their "usual" diets and LC diet. Subjects were instructed to follow the first two phases of the diet described in Dr. Atkins' New Diet Revolution (2 weeks each). Total daily intake of calories and nutrients were calculated from 3-day food diaries. Body weight was measured at the end of each 2-week diet session. All enrolled subjects completed the study (age = 39.8 +/- 8.1 years, BMI = 36.6 +/- 6.6 kg/m(2)). Mean caloric intakes were 1400 +/- 472 kcal/day (Induction diet) and 1558 +/- 490 kcal/day (Ongoing Weight Loss diet) both p </= 0.001 compared to "usual" (Baseline diet) 2481 +/- 723 kcal/day. Body weights were 107.4 +/- 24.2 kg, 103.6 +/- 23.0 kg and 102.1 +/- 22.6 kg at the conclusion of the Baseline, Induction, and Ongoing Weight Loss diets, respectively (both p </= 0.001). Decreases in daily caloric intake correlated with weight loss. Pearson correlation coefficients were, r = 0.64 (p </= 0.001) and r = 0.40 (p </= 0.001) for Induction and Ongoing Weight Loss diets versus "usual" diet. Caloric intake is decreased when otherwise healthy overweight and obese adults self-implement Atkins' Induction and Ongoing Weight Loss diets and significantly altered their dietary micronutrient intake. Weight loss can be explained by the self-selected lower caloric intake on The Atkins' Diet.