How processed foods make us fat
New research suggests when it comes to weight gain, processed foods deserve their bad boy reputation.
Do you start your day with sugary cereal or a pre-packaged muffin? Or do you have low-fat yoghurt with fruit for breakfast?
Ultra-processed foods have been growing in popularity worldwide, making up nearly half of the Australian diet.
However, a new Australian study of nearly 10,000 people’s eating habits provides further evidence processed foods are the leading cause of increasing obesity rates in the Western community.
Researchers found the low-protein composition in processed foods may drive cravings and the overconsumption of carbohydrates and fats to make up for it.
With ultra-processed foods having been linked to an increased risk of type 2 diabetes, cardiovascular diseases and premature death – is it time to ditch the fizzy drinks and cheap heat-and-eat meals?
- Diet discipline: Lost sight of your healthy eating goals? Bring them back into focus
What are processed foods?
“Strictly speaking a processed food is any food that is no longer in its natural state,” naturopath and nutritionist Madeline Calfas says.
This includes biscuits, meat pies, butter, chocolate, salty snacks, ready-to-eat meals, pre-prepared sauces, canned or processed meats and frozen meals.
Meanwhile, unprocessed foods are those in still in their original form or very close to it, nutritionist and recipe developer for The Fast 800 Gabrielle Newman says.
This means fresh fruit, vegetables, meat and fish, nuts and seeds, legumes and grains.
“Frozen fruits and vegetables that are essentially snap-frozen at the time of harvest are minimally processed and are a healthy choice,” Gabrielle says
What do processed foods do to our body?
The convenience of preparing processed foods for a quick meal is simply one of its appeals, Madeline says.
“Food that is easy to cook or prepare and has loads of salt, fat and sugar goes a lot further to ping our dopamine receptors, our ‘feel good’ hormone, than a salad,” she says.
However good it may taste, the high level in sugars, salt and saturated fat may increase the risk of obesity, heart disease and some cancers.
Plus, Gabrielle says there is a risk of diabetes because of the rise in blood sugar levels.
“A diet high in sugar leads to insulin resistance and eventually Type 2 diabetes… and often goes hand-in-hand with high blood pressure and cholesterol implications,” she says.
She adds a diet high in salt could put unnecessary pressure on their kidney, increasing fluid in the body.
“This excess fluid means extra blood volume, pressure on your heart and so an increase in blood pressure, heart disease and kidney issues.”
Refined or processed foods are also known to be low in fibre, which Gabrielle says is often removed during processing.
Why do processed foods make us gain weight?
Essentially, processed foods make us want more.
“Processed foods have increased palatability and trigger areas of the brain associated with enjoyment,” Professor John Dixon, obesity expert at Baker Heart and Diabetes Institute, says.
“So, people eat more and put on weight, but it’s not just fast foods that have this effect.
“The best restaurants and celebrity chefs do the same thing with the foods they offer.”
Not only that, according to the recent Australian study, we need protein to feel full, and processed foods are often lacking in this macronutrient.
How much protein is accessible in refined food depends on the level of processing, which could range from small protein composition to barely any at all, Madeline says.
“It is well-known that a diet higher in protein and ‘good fats’ will keep your body feeling fuller and more satiated for longer.”
The US researchers say the texture of processed foods may also make us eat faster.
“If you’re eating very quickly, perhaps you’re not giving your gastrointestinal tract enough time to signal to your brain that you’re full,” notes Kevin Hall, of the National Institute of Diabetes and Digestive and Kidney Diseases.
“When this happens, you might easily overeat.”
To make matters worse, the high sugar, sodium and saturated fat levels are likely to make you feel lethargic and move around less as a result, Madeline says.
“What does this all mean? Hello, muffin top!”
- Obesity crisis: The food choices that are making us fat
Prof Dixon’s top tips to cut back on processed foods include:
- Take your diet back to basics and enjoy natural foods. The Mediterranean diet is a good starting point.
- Introduce natural, unprocessed foods to children when they are young to develop healthy eating habits for life. “Add vegetables one at a time so children get used to vegetables,” says John. “And give children water or milk to drink.”
- Keep treat foods as treats – have them occasionally and not every day.
Written by Sarah Marinos. Updated by Melissa Hong November 2022.
