Failure To Thrive

Overview

Failure to thrive is a term doctors use when a person is not growing, gaining weight, or developing the way we would expect for their age. It is used most often for babies and young children, but it can also describe older adults who slowly lose weight, muscle, and strength. Failure to thrive is not a disease on its own. It is a sign that something else is going on, such as not getting enough food or nutrients, a health problem, or a hard situation at home. Once the cause is found and helped, most people start to grow and feel better again.

It is fairly common in young children. Around one in ten children seen in general practice, and more in some hospital settings, have some slowing of growth or weight gain at some point. In older adults, slow weight loss and frailty are also common and often not talked about.

It most often affects babies and children under five, especially those born early or with a low birth weight. It can also affect children with long-term health conditions, feeding difficulties, or who live in difficult circumstances. In older adults, it is more likely in people living alone, those with memory problems, depression, trouble chewing or swallowing, or long-term illness.

Symptoms

Common symptoms

• Weight that stays the same or goes down instead of slowly going up
• Growing more slowly than expected in height or length
• Clothes or shoes not needing to be replaced as often as expected
• Eating less than usual or showing little interest in food
• Tiredness, low energy, or being less active than usual
• Getting infections more often or taking longer to recover
• Slow development of new skills, such as sitting, walking, or talking

Symptoms in children

• Not gaining weight over weeks, or weight dropping on the growth chart
• Being very sleepy or very fussy during feeds
• Latching or sucking poorly, or taking very short feeds
• Fewer wet nappies than usual, or dark, strong-smelling urine
• Loose or dry skin, sunken cheeks, or a sunken soft spot on a baby's head
• Delayed smiling, rolling, sitting, or walking
• Being quiet and less interested in people and surroundings
• Frequent vomiting, diarrhoea, or refusing feeds

Symptoms in older adults

• Losing weight without trying
• Losing muscle, especially in the arms and legs, and feeling weak
• Poor appetite or feeling full very quickly
• Trouble chewing, swallowing, or holding cutlery
• Tiredness, confusion, or low mood
• More falls, pressure sores, or infections
• Clothes and rings becoming loose

Causes

Main causes

• Not getting enough calories or nutrients, for example because of poor feeding, a poor diet, or food insecurity
• Feeding difficulties such as poor sucking, a tongue-tie, or a cleft palate
• Reflux, where milk comes back up, or ongoing vomiting
• Food allergy or intolerance, such as to cow's milk protein
• Coeliac disease, where the body reacts to gluten and cannot absorb food well
• Long-term conditions affecting the heart, lungs, kidneys, liver, or gut
• Ongoing infections, anaemia, or a thyroid problem
• Developmental or neurological conditions that affect eating and swallowing
• In older adults: dementia, depression, trouble swallowing, dental problems, loneliness, alcohol misuse, or side effects of medicines
• Family stress, money worries, mental health difficulties, or a lack of support at home

Risk factors

• Being born early or with a low birth weight
• Being a twin or triplet
• Feeding problems in the first weeks of life
• Long-term illness or repeated hospital stays
• Developmental delay or disability
• Living in poverty or having limited access to food
• A parent or carer who is very stressed, unwell, or without support
• For older adults: living alone, recent bereavement, memory problems, or difficulty shopping and cooking

When to see a doctor

See a doctor urgently if:

• You are worried your baby or child is losing weight or not growing
• Feeds are getting shorter, weaker, or more difficult
• Your child is much more sleepy or much more fussy than usual
• An older adult has lost weight without trying over the past few months
• Someone is finding it hard to swallow, or coughs or chokes when eating

Book a routine appointment if:

• You want your child's growth checked at a routine appointment
• You need help with fussy eating or mealtimes that feel stressful
• You are worried about food costs or getting enough healthy food
• You would like advice on whether a vitamin supplement is needed
• An older adult seems to be eating less or losing interest in food

Diagnosis

A doctor starts by measuring weight, length or height, and head size, and plotting these on a growth chart. One measurement tells you little, but a pattern over weeks or months is very useful. They will ask about feeding, eating, and what a typical day looks like, and will examine the person. For older adults, the focus is on weight history, appetite, swallowing, mood, memory, and practical difficulties at home. Often a dietitian is involved, and social or practical support may also be offered.

Tests that may be done

• Repeated weight and height measurements over time, plotted on a growth chart
• A food and feeding diary kept over a few days
• Blood tests to check for anaemia, coeliac disease, thyroid problems, and vitamin levels
• Urine and stool tests to look for infection or poor absorption
• A check for food allergies if these are suspected
• A swallowing assessment by a speech and language therapist if eating is difficult
• Other tests depending on what the doctor finds, such as heart, lung, or gut checks

What to expect at your appointment

You may be asked to come back for repeat weigh-ins, which can feel like a lot of appointments but gives the clearest picture. Bring notes about feeds, meals, and nappies or bowel habits if you can. It can help to write down your questions beforehand and to bring someone with you. Nothing is decided from a single number, and you should feel able to ask what each test is for.

Treatment

Treatment aims at the cause. That might mean helping feeding and eating, adding more energy and nutrients to what is eaten, treating a health problem, or arranging practical support at home. Help is usually a team effort between you, your doctor, a dietitian, and sometimes a nurse, health visitor, speech and language therapist, or social worker. The plan should fit your family's real life, and you should be told why each step is being suggested.

Self-care at home

• Keep a simple diary of feeds, meals, and weight checks to share at appointments
• Offer small, frequent meals or feeds rather than expecting one big meal
• Keep mealtimes calm and relaxed, and avoid forcing food or turning meals into a battle
• Add extra energy and nutrients to everyday foods, such as full-fat milk, cheese, olive oil, or nut butters where safe
• Ask your clinician whether a vitamin supplement is needed
• Attend follow-up weigh-ins, even when things seem to be improving
• Ask for help with food costs, food banks, or meal services if money is tight
• For older adults, make eating easier with softer foods, a comfortable seat, and company at mealtimes

Medical treatments

Doctors and dietitians usually start by treating the underlying problem, such as reflux, constipation, an infection, anaemia, or a condition affecting the gut. A dietitian can suggest ways to add energy and nutrients to normal foods, and may recommend prescribed nutritional drinks or supplements for a short time. Feeding therapy or support from a speech and language therapist can help with sucking, chewing, and swallowing. If allergies are involved, a planned way of avoiding the food and replacing what it provides is arranged. Emotional and practical support for parents and carers is part of treatment too, and you should never feel judged for asking for it.

When is surgery considered?

Surgery is only needed in a small number of cases, for example to repair a cleft palate or to treat a serious physical blockage or severe reflux that has not improved with other treatment. Your medical team would explain the reasons carefully and discuss the benefits and risks with you first.

Living with this condition

Day-to-day life with a child who is not growing well can feel exhausting and worrying. Focus on small, steady steps rather than perfect meals. Keep a routine, celebrate small gains, and remember that weight often goes up slowly. For older adults, a regular eating routine, shared meals, and help with shopping and cooking can make a big difference. Keep a folder of appointments and notes so nothing gets lost.

Lifestyle tips

• Keep regular meal and snack times so eating becomes a habit rather than a struggle
• Eat together where possible, as company helps appetite
• Stay gently active, as movement helps appetite and builds strength
• Get enough sleep, and rest when you can
• Limit drinks just before meals so they do not fill small stomachs
• Keep up with routine health checks and vaccinations
• Ask family, friends, or local services for practical help with shopping, cooking, or childcare

Diet and exercise

There is no single perfect diet. The aim is regular, nourishing food with enough energy and protein to support growth and strength. For children, full-fat dairy and energy-rich foods are often helpful unless a doctor advises otherwise. For older adults, protein at each meal, plenty of fluids, and soft, easy-to-chew options help. Gentle movement, such as walking, stretching, or playing, supports appetite and muscle strength. Ask to see a dietitian for advice tailored to you or your child.

Mental health and emotional wellbeing

It is very common to feel guilty, anxious, or judged when a child is not growing well, or when a parent or partner is losing weight. Those feelings are understandable, and they are not a sign you are failing. Tell your doctor how you are feeling, as support for the carer is part of good care. For older adults, low mood and loneliness can both cause and follow poor appetite, so it is worth raising them. If you ever have thoughts of harming yourself, contact your local emergency number or a crisis line straight away.

Prevention

Not every case can be prevented, but a lot can be done to lower the risk. Regular growth checks, early help with feeding, treatment of health problems, and practical support for families all help. Keeping an eye on weight in older adults, and acting early on appetite, swallowing, or mood changes, also makes a difference.

Vaccines

Keeping up with routine vaccinations, including childhood immunisations and recommended seasonal vaccines, helps prevent infections that can affect eating, growth, and strength. Ask your doctor or pharmacist which vaccines are advised for you or your child.

Screening programmes

Growth is checked at routine baby and child health reviews, which is why attending them matters. For older adults, weight and nutrition checks can be done at routine appointments or during hospital stays. If you are worried at any time, you can ask for a check even if one is not due.

Complications

If left untreated

• Slower physical growth and, in children, delayed development of movement, speech, or learning
• A weaker immune system and more frequent or longer infections
• Anaemia and low levels of vitamins and minerals
• Weaker bones and muscles
• Longer or repeated hospital stays
• In older adults: frailty, falls, pressure sores, and a higher risk of serious illness
• Stress, worry, and low mood for the person and their family

Long-term outlook

The outlook is usually good, especially when the cause is found and help starts early. Many children catch up in growth and development once feeding and health improve. For older adults, steady support with eating, health, and daily life can improve strength and wellbeing. Progress can be slow, so try to measure success over months rather than days, and keep talking to your care team about what is working.

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