Poor Weight Gain / Underweight in Children

“My child is eating, but not gaining weight. Should I worry?”

Short Answer:

“Not all small children are unhealthy, but poor weight gain deserves assessment when growth is slower than expected.”

Some children are naturally slim because of family traits. What concerns doctors is when a child is gaining weight too slowly, stops following their usual growth curve, or loses weight over time.

Growth is one of the best indicators of a child’s overall health. A single weight reading is less important than the pattern of growth over time.

Common Causes

Inadequate calorie intake

• Picky eating
• Small appetite
• Excessive milk intake reducing appetite for food
• Feeding difficulties
• Limited food variety

Increased calorie needs

• Frequent infections
• Heart or lung conditions
• Chronic illnesses

Reduced absorption of nutrients

• Coeliac disease
• Chronic diarrhoea
• Some gastrointestinal conditions

Other contributing factors

• Prematurity
• Developmental or behavioural feeding difficulties
• Psychosocial or environmental factors
• Less commonly, hormonal or metabolic disorders

“My child is small like the parents. Is that normal?”

Sometimes, yes.

A child may be naturally small if there is a strong family history of smaller body size. However, we still look at:

• Whether the child is following their own growth curve
• Height and weight together
• Growth over several months
• Feeding and developmental history

“My child is very active but doesn’t gain weight.”

Active children may burn more calories, but persistent poor weight gain is not explained by activity alone. We need to consider whether the child is taking in enough calories and whether there is any underlying medical cause.

What Parents Can Observe

• Appetite and feeding behaviour
• Types of food eaten and meal patterns
• Excessive milk or snack intake
• Vomiting, diarrhoea or constipation
• Frequent cough, wheeze or infections
• Tiredness or reduced activity
• Weight changes over time
• Whether clothes or nappies are becoming looser

Supportive Care at Home

• Offer 3 meals and 2–3 nutritious snacks daily
• Include calorie-rich nutritious foods such as eggs, fish, meat, legumes, nut butters (if age-appropriate), avocado and dairy products
• Limit excessive juice and sugary drinks
• Avoid pressuring or forcing the child to eat
• Keep mealtimes calm and predictable
• Encourage self-feeding when developmentally appropriate

When to Arrange a Paediatric Appointment

What to Expect During the Consultation

The paediatrician may review:

• Growth charts and previous weights
• Pregnancy and birth history
• Diet and feeding pattern
• Milk intake
• Bowel symptoms
• Medical and family history
• Development and activity level

Examination may include assessment of weight, height, body proportions, hydration and signs of nutritional deficiency or underlying illness.

Blood tests or other investigations are considered only when the history or examination suggests they are needed.

Our Approach

At Southern Child Specialist Clinic, we focus on identifying why a child is not gaining weight adequately.

Depending on the assessment, we may provide:

• Growth chart interpretation
• Dietary and calorie optimisation advice
• Feeding and mealtime strategies
• Assessment for nutritional deficiencies
• Investigation for underlying medical causes when indicated
• Follow-up to monitor growth over time
• Referral to a dietitian or other specialists when needed

Our goal is not simply to increase the number on the weighing scale, but to support healthy growth, nutrition and overall development.