Calorie restriction improved diet quality in healthy adults
In a randomized trial of 220 healthy adults, the calorie-restriction group cut intake by 15.2% over 12 months, against a 25% target.
220 participants, 12 months, blinded, multicenter, sample size calculated, registered NCT00427193
Limit: Nutrition counseling given only to calorie-restricted participants also encouraged healthier food choices
Edited by Boris Djordjevic · AgingResearch.News
This secondary analysis of a randomized trial included 220 healthy adults with normal weight or overweight: men aged 21–50 and women aged 21–47. Participants were assigned to a 25% calorie reduction or unrestricted eating for two years. This analysis covered the first 12 months. The calorie-restriction group received meals for 27 days, then chose their own foods.
Compared with unrestricted eating, calorie restriction improved diet quality while maintaining adequate vitamin and mineral intake. The increase in fiber intake was 8.6 grams per day greater, and the decrease in added sugar was 16.9 grams per day greater. Participants also shifted toward more fruits, vegetables, whole grains and low-fat dairy, and away from refined grains, sugary drinks and red meat.
Why it matters
Adequate nutrition is important for healthy aging. The authors suggest that implementing calorie restriction with a healthier diet can help reduce chronic disease risk.
Caveats
Diet records relied on self-report and underestimated calorie intake compared with an independent measurement method. The results concern healthy adults in the stated age ranges, not older adults or people with cardiovascular disease or diabetes, whom the trial excluded.
From the paper
- Participants
Healthy individuals (N=220) with normal weight or overweight with a body mass index (BMI) between 22.0 and 28.0 kg/m² aged 21–50 years (males) and 21–47 years (females to avoid menopausal onset) were randomized to CR (N=145) or an ad libitum (AL) (N=75) control group.
- Ages
Participants were 38.1±7.2 years old and most identified as white (77%), and 48% had normal weight and 52% had overweight.
- Duration
Therefore, only baseline and 12-month measurements were included in the present analysis for both the CR and AL groups.
- Result
There was a significant difference in the change in self-reported total energy intake between CR and AL groups, suggestive of greater decreases in the CR group from baseline to 12 months (−235 kcal; 95% CI: −356, −114; P<0.001).
- Body weight
At 12 months, participants in the CR group experienced a mean weight loss of 8.3±3.1 kg, corresponding to 11.5±4.0% of baseline body weight.
- Diet quality
As a result, there were significant between-group differences in the changes of intake for alcoholic beverages, sugar sweetened beverages, low fat/fat-free dairy, fruit juice, mixed grain products, refined grain products, refined grain sugar and sweets, other vegetables, whole grain products, total fruits, vegetables (green, yellow, red, orange), meat (red, game, organ), and reduced fat sauces/dressings/gravy from baseline to 12 months (all Ps<0.05 …
Quoted word for word from the full text on PubMed Central.
Caloric restriction is part of Bryan Johnson's Blueprint
The paper
Self-selected dietary intake and association with achieved caloric restriction in CALERIE™ 2
Pennington Biomedical Research Center
Critical Reviews in Food Science and Nutrition, May 22, 2026, Open access, accepted manuscript