Weight gain and autism

Weight gain can be a concern for children with autism. As of 2018, 25% of children aged 2-17 in Australia were considered overweight. This figure has remained stable for over a decade, with 1 in 4 children being affected by overweight and a smaller 8% affected by obesity. Children with a disability such as autism are more likely to be overweight than age-related peers. This is not about body-shaming, but about supporting children with autism to have healthy habits that support their long-term health outcomes.

What are the impacts of weight gain?

The Australian Institute of Health and Welfare report that there are increased health risks associated with being overweight. It can lead to poor physical health, low performance in school, and an increased risk of being obese in adulthood. Obesity is also linked to diabetes, a higher chance of heart disease, increased chance of being bullied and poor mental health including depression. In addition, it’s associated with a reduced life span of 5-20 years according to Thom et al.

Around age 9, a higher proportion of children move from normal weight to under or over weight, indicating that addressing weight is important for young children. Weight is often programmed during childhood, so prevention of big weight changes early in life is important for life-long health as an adult.

What are the risk factors?

Unhealthy eating is a common contributor to weight gain for autistic children. Children with autism may have a restricted diet, with a preference for energy-dense and processed foods, sweet drinks and snack foods. They are more likely as part of their ‘beige diet‘ to have reduced vegetable and fruit intake. Children with autism may also tend to over eat. They may have a decreased sense of interoception to tell them when they are full, or enjoy the oral sensory-seeking input of eating tasty food. Also, food treats may be used as part of rewards in behavioural training strategies (giving a lolly for successful toilet visits, for example), which can increase sugar and calorie intake.

Lack of physical exercise is another contributor to weight gain in autistic children. Difficulties in engaging in physical activity due to social challenges or low motor control/balance/coordination can contribute to low rates of sport participation for autistic children.

Managing behaviours associated with ADHD, ASD and anxiety with drugs can also contribute to weight gain. Drugs that address hyperactivity and aggression often have weight gain as a side effect, with one study reporting over 1 kg of weight gain in 8 weeks of use compared to a placebo.

Poor sleep quality may also contribute to weight gain. Autistic children often report difficulties falling asleep, staying asleep, and getting enough sleep. This can be a contributing factor to weight gain.

Weight management recommendations

A recent study from 2020 gives recommendations specifically for weight management in autistic children, as suggested by an expert committee.

They recommend that:

  1. Children with ASD have regular monitoring of their weight
    Young children from pre-school age can begin to show signs of weight gain that last into adulthood. The advice from this study is to monitor weight and BMI of children from age 2.
  2. Have positive conversations about health
    The study notes that being overweight can contribute to being bullied, depression, low self-esteem and weight-related stigma and frustration. They recommend a positive and motivation framing of conversations, rather than lectures or admonishments. Set goals together about healthy eating and physical activity.
    The study recommends a large number of activities at home to support this. Part of the table of suggestions is included below, but see the full article for all strategies they suggest.
From: https://publications.aap.org/pediatrics/article/145/Supplement_1/S126/11560/Weight-Management-in-Primary-Care-for-Children?autologincheck=redirected

The study also suggests addressing the risk factors in a holistic approach to weight gain and autism.

This includes:

  1. Strategies for improving sleep quality
  2. Strategies for increasing food variety, nutrition and fibre intake
  3. Strategies for increasing physical activity

Body confidence through healthy living

For the most part, recommendations from the literature discourage focusing on the weight or scales. They focus on being healthy, active, and happy with what your body can do i.e. body confidence.

Weight aside, building body confidence is about having a body that can do things (like climb trees, run around, and play). Loving and respecting yourself is about looking after your body. This includes having the knowledge and skills to be healthy. Obsessively focusing on weight is unlikely to bring out good health – just look at the dieting industry! But a focus on being healthy is important.

So talk about what good nutrition looks like. Talk about how it’s great that when they eat a balanced diet, their bodies have the fuel to run around and be active, and do the things they want. Regardless of what that body looks like, celebrate what it enables you to do. Encourage healthy eating of ‘everyday food’ and don’t have lots of ‘sometimes foods’ like sugary drinks and junk food in the house.

The parenting book Raising girls who like themselves, includes a big chapter on body confidence. They don’t recommend talking about BMI, but about natural body weight and wellness. That is, a natural body weight is whatever it happens to be when living a healthy and active life. If you’re concerned about being above natural body weight, they suggest that rather than focus on appearance or weight, focus on healthy behaviours like being active and eating healthy.

From Rick Kausman, “Focus on the process of living a healthy life, rather than weight loss as a goal”.

Conclusion: weight gain and autism

Weight gain in children with autism is a commonly researched topic. It is well described in the literature, and considered a concern for long-term health outcomes of autistic people. Developing positive wellness habits of nutritious eating and regular physical activity while young is important and where the emphasis should be.


Thom, R.P., Palumbo, M.L., Keary, C.J. et al. Prevalence and factors associated with overweight, obesity, and hypertension in a large clinical sample of adults with autism spectrum disorder. Sci Rep 12, 9737 (2022). https://doi.org/10.1038/s41598-022-13365-0

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