Baby weight gain and starting solids

Weight gain slows down after 6 months

Many parents notice that the big monthly jumps on the scale get smaller around the time solids start. That’s expected. The NHS says babies usually gain weight most rapidly in the first 6 months, and that their rate of growth gradually slows as they become toddlers and are more active. The AAP says babies double their weight by about 6 months and triple it by around 1 year.

After the first birthday, growth slows further. The AAP says many parents notice a sharp drop in appetite at this point, because a toddler really doesn’t need as much food.

Solids aren’t meant to speed up weight gain

At first, how much your baby eats matters much less than getting them used to eating. The NHS says babies still get most of their energy and nutrients from breast milk or formula when they start solids, and that the important thing early on is learning new tastes and textures and how to move food around the mouth and swallow.

So a few spoonfuls a day won’t change the scale much, and they don’t need to. Keep milk feeds going as solids build up over the months. See milk and solids together and how much breast milk or formula.

Don’t add cereal or anything else to a bottle to “fill your baby up”: the NHS says to put only breast milk or formula in a bottle.

How growth is checked

Your baby’s weight and length are measured at routine visits and plotted on a growth chart.

• In the US, the WHO growth standards are used for babies and children from birth to 2 years (CDC). The AAP says that in the first 2 years, the chart covers weight, length and head size. From age 2, one chart follows your child through age 20, and BMI (body mass index) is added.
• In the UK, your baby’s growth is recorded on UK-WHO centile charts in the personal child health record, the red book (NHS). After the first 2 weeks, the NHS says babies should be weighed no more than once a month up to 6 months, once every 2 months from 6 to 12 months, and once every 3 months after age 1, unless you ask or there are concerns. From age 2, a health visitor may work out your child’s BMI.

The WHO built its standards from more than 8,000 children in six countries, including the US, raised in conditions that support healthy growth, with the breastfed child as the norm (WHO). The NHS says the charts show the pattern of growth healthy children usually follow, whether they’re breastfed, formula fed or both.

Reading the chart

The curved lines are called centiles in the UK and percentiles in the US. A baby on the 25th percentile weighs more than about 25 out of 100 babies of the same age and sex.

• It’s not a grade. The AAP says the 10th percentile is no better or worse than the 90th. What matters is the trend.
• Look at the line, not the dot. The AAP says one point on the chart is far less useful than several points over time.
• Some movement is normal. The NHS says a baby’s weight may go up or down by 1 centile line, but crossing 2 lines is less common and is worth talking to your health visitor about.
• Weight and length can differ. It’s normal to be on different centiles for weight and length, though they’re usually fairly similar (NHS).
• Illness can cause a dip. Weight gain may slow while your baby is ill and usually returns to normal within 2 to 3 weeks (NHS). See feeding a sick baby.

Your baby follows their own curve

Every baby’s chart looks different, even compared with a brother or sister (NHS). The AAP says genetics, environment, nutrition, activity and health all influence how a child grows. A small baby who stays on their own line is usually doing just as well as a big baby who stays on theirs. Ask your pediatrician or health visitor to show you the chart and explain the trend; the AAP encourages parents to keep asking until it makes sense.

If your baby is gaining slowly or losing weight

Talk to your pediatrician, GP or health visitor. Doctors call it faltering weight when a child isn’t gaining enough, is losing weight, or the doctor is concerned about their weight (AAP). The AAP says it’s common, affecting up to 1 in 10 children seen in primary care, and that the doctor will look at the growth history and examine your child. Most of the time, no tests are needed. The plan depends on the cause and may involve changes to what your child eats, how they’re fed, or both. Your child may be referred to a dietitian or a feeding therapist (AAP).

While you wait for advice, keep feeding responsively. The NHS says not to force your baby to eat. Offer food when your baby is alert and not too tired, keep offering milk feeds, and include iron-rich foods. See is my baby eating enough? and iron-rich first foods.

If your baby is on a high centile

A big baby who is following their own line is growing as expected (AAP, NHS). Don’t put a baby or toddler on a diet, and don’t cut back their milk or food because of their weight.

• Fat matters at this age. The AAP says not to restrict fats for 1-year-olds: babies and young toddlers should get about half their calories from fat.
• Let them decide how much. The AAP says your role is to offer healthy food in sensible portions, and your child’s role is to decide how much to eat.
• Serve family food without added sugar or salt, and stop when your child shows they’re full. See hunger and fullness cues.

If you’re worried, ask your pediatrician or health visitor to look at the trend with you. Any change to your child’s diet should come from them.

When to call your doctor

Talk to your pediatrician, GP or health visitor if your baby:

• is losing weight, or isn’t gaining weight as expected (AAP)
• has crossed 2 or more centile lines on their chart, up or down (NHS)
• has a weight concern you’d like explained; you don’t need a red flag to ask

Signs of dehydration need a call to your doctor right away. The AAP says to call your pediatrician immediately if your baby has fewer than 6 wet diapers a day, a dry mouth, fewer tears, a sunken soft spot on the head, or is playing less than usual. The NHS says to ask for an urgent GP appointment or call 111.

When to call for emergency help

Call 911 or go to the emergency room if your baby:Call 999 or go to A&E if your baby:Call your local emergency number (such as 112 in Europe or 000 in Australia) or go to the emergency department if your baby:

• is floppy, very sleepy, difficult to wake, or can’t be woken
• is struggling to breathe or breathing very fast
• has blue, grey, pale or blotchy skin, lips or tongue, or skin that feels cold
• hasn’t had a wet diaper or peed in 12 hours
• has signs of severe dehydration: sunken eyes, excessive sleepiness, or cool, discolored hands and feet

The first four signs are on the NHS list for calling 999 or going to A&E. The last comes from the AAP’s list of severe dehydration signs: the AAP says to tell your pediatrician immediately, and this site sends them to emergency care, because the NHS says similar signs with dehydration can mean shock, a serious complication. Trust your instincts: if you think something is seriously wrong, get help.

Where US and UK advice differs

• The charts. In the US, WHO charts are used from birth to 2 years (CDC), then a chart for ages 2 to 20 (AAP). In the UK, growth is plotted on UK-WHO charts in the red book.
• Who checks. In the US, your pediatrician reviews growth at well-child visits (AAP). In the UK, health visitors and GPs do it at reviews, and the NHS sets a maximum for how often a healthy baby is weighed.
• The words. US charts talk about percentiles; UK charts call them centiles. They mean the same thing.
• The core is the same. Both look at your baby’s pattern over time, not a single weight.