A new study looking at the types of fat people eat has found those who consume more ‘healthy fats’ are less likely to put on weight than those who eat ‘unhealthy fats’, despite eating the same number of kilojoules (1). 

The findings, by Deakin University researchers, provide further evidence of the benefits of a diet high in ‘healthy’ unsaturated fats, such as those from nuts, seeds, avocados, olive oil and fish.

Unsaturated fats can be part of an overall healthy dietary pattern for preventing weight gain.

About the research

Lead researcher Barbara Brayner and her colleagues looked at links between dietary patterns – with varying proportions of saturated fatty acids (SFA), monounsaturated fatty acids (MUFA) and polyunsaturated fatty acids (PUFA) – and obesity, abdominal obesity, and type 2 diabetes.

They used data from more than 16,000 adults, aged 40-69 years, from the large UK Biobank study.

Study participants were tracked for an average of six years to understand if different dietary fats, within the context of an overall diet, led to different weight outcomes.

Key findings:

• People eating a diet higher in unsaturated ‘healthy’ fats, from foods like nuts, seeds and avocado, were less likely to put on weight as they aged, even though their kilojoule intake was similar.

• A dietary pattern characterised by foods higher in SFA was associated with obesity and abdominal obesity incidence (but not type 2 diabetes).

• Adults who ate a diet higher in saturated (or ‘unhealthy’) fats, from foods such as butter, high-fat cheese, red and processed meat and deep-fried foods, were 24% more likely to develop obesity, and 19% more likely to have abdominal obesity.

The findings suggest that, along with energy (kilojoule) intake, the type of dietary fat consumed may also influence obesity risk.

While this study found no link between the dietary patterns and incidence of type 2 diabetes, the researchers suggest a longer follow-up may have been needed to detect these associations.

Did you know? A 24-year study, which tracked more than 121,000 US-based adults, showed a 5% increase in energy intake from saturated fats was associated with 0.61kg more weight gain, whereas a 5% increase in energy from PUFAs was linked with -0.55kg less weight gain (2).

Five ways to add more healthy fats to your day:

• Snack on a handful of nuts
• Spread avocado on toast, sandwiches or whole grain crackers
• Combine tahini (ground sesame seed paste) and lemon for a creamy salad dressing
• Add tinned fish to your lunch-time wrap or salad
• Cook with healthier oils, like nut, avocado or olive oil.

According to the researchers, from Deakin University’s Institute for Physical Activity and Nutrition (IPAN), the study is the first large scale look at the impact of fat type on developing obesity within the context of an overall diet.

The study was published in The Journal of Nutrition. 

Did you know? Another recently-published study – a major review of more than 20 years of research – found strong evidence that eating nuts does not cause weight gain, and can even help keep weight in check (3).