This comes as protein continues to dominate global product innovation and marketing – particularly in snacks, beverages, and meal replacements – often positioning it as solutions to weight and health concerns.
At the same time, recent analyses of Japanese children’s diets show declining intakes of fish, dairy and fruit, reinforcing concerns that meal balance – not just nutrient fortification – may be eroding early in life.
Impact of nutrient intake on weight management
Researchers found no consistent relationship between habitual protein intake and adiposity rebound (AR) – a normal phase in early childhood when body fat reaches its lowest point before rising again, typically between ages five and seven.
Instead, the findings suggest that regularly eating balanced meals may be more strongly associated with lower overweight and obesity risk than focusing on individual nutrients or food groups.
Data from Japan’s National Health and Nutrition Survey showed that a higher frequency of meals comprising a staple food, main dish and side dish was linked to higher nutrient intake and better overall diet quality.
These findings prompted researchers to examine whether the frequency of such balanced meals was associated with early adiposity rebound in preschool children.
An earlier-than-usual adiposity rebound is linked to a higher risk of overweight and obesity later in life.
Japan’s recommendation for a well-balanced diet
The National Health Promotion Initiative in Japan (Healthy Japan 21, Phase III) defines a well-balanced diet as meals that include staple foods, along with main and side dishes.
Staple foods comprise carbohydrate-rich foods, such as rice, bread, and noodles.
The main dish includes protein-rich foods, such as meat, fish, eggs, and soy products, while the side dish consists of vegetables, mushrooms, seaweed, and root vegetables.
“[A] longitudinal study showed that a lower frequency of consuming meals with staple foods, main dishes, and side dishes was associated with a higher risk of weight gain over 3 years,” the researchers wrote in Nutrients.
“In contrast, research that focused on single nutrients and AR found no consistent relationship between habitual protein intake during childhood and AR. This suggests that the frequency of balanced meal intake, rather than individual nutrient or food group intake, has greater predictive accuracy for overweight and obesity risk.”
The study
The analysis drew on a nationwide survey of 688 mothers with children aged three to six.
Children’s dietary habits were assessed using a validated Japanese nutrition screening questionnaire, which measured how often meals included staple foods, main dishes and side dishes.
Researchers accounted for factors that could influence weight outcomes, including age, sex and parental obesity.
Risk scores reflecting lower frequency of balanced meals were calculated for staple foods, main dishes, and side dishes.
An overall risk score (0–12 points) for staple foods, main dishes, and side dishes was calculated, with higher scores indicating poorer dietary habits.
The median total risk score was 2.9 in the non-AR group, compared with 3.5 in the AR group. Risk scores for each meal component — staple foods, main dishes and side dishes — were also consistently higher among children with AR.
Of the 688 children, 193 (28.1%) showed signs of early adiposity rebound and already had significantly higher BMI at age three and at their most recent measurement.
Children with poorer overall diet quality were more than twice as likely to experience early AR compared with those who ate balanced meals more frequently.
Early AR was observed in 24.1% of children with better dietary balance, compared with 32.6% of those with poorer diets – an 8.5-percentage-point difference that reinforced the link between infrequent balanced meals and early weight gain.
Why a balanced meal is important
Balanced meals help provide sufficient energy, protein and micronutrients, supporting stable appetite regulation and appropriate weight gain in early childhood, the researchers noted.
Macronutrients, such as protein, can influence satiety by stimulating gut–brain hormones such as glucagon-like peptide-1 (GLP-1), leading to reduced energy intake.
However, regularly omitting key meal components – whether staple food, main dish, or side dish – may disrupt overall energy balance and appetite control.
Such disruptions may alter hormonal signalling related to hunger and fullness, increasing the likelihood of excess energy intake over time.
The researchers suggested that repeated exposure to well-structured meals during early childhood may also shape food preferences and support self-regulation of energy intake, both of which are critical for long-term weight control.
Supporting this, previous studies in Japan have shown that frequent consumption of meals comprising staple foods, main dishes and side dishes is associated with higher intakes of energy, protein, vitamins and minerals, as well as better adherence to national dietary guidelines. Higher adherence has also been linked to lower all-cause and cardiovascular mortality risk in adults.
Source: Association Between Adiposity Rebound and the Frequency of Balanced Meals Among Japanese Preschool Children: A Cross-Sectional Study
Journal: Nutrients
Authors: Tada, Y. et. al.
