7th December 2012 - Switching from fatty foods to lower fat alternatives can lead to reductions in weight in adults, says a new study.
Crucially, this appears to be the case even in those who have not gone on any diet with the intention of being slimmer.
"I think people might be surprised that you can lose weight without intending to," says lead researcher Lee Hooper from the University of East Anglia's Norwich Medical School.
"These are not people on diets, these are not people trying to cut down on their calorie intake or their energy intake," she tells us; "but they're people who've just been sensible about their eating and actually they've lost weight - and that weight has been maintained for many years".
The ideal amount of fat needed by humans is unclear and was recently debated by the United Nations and the World Health Organisation (WHO). Experts at the meeting agreed that an understanding of the relationship between the total amount of fat consumed and body weight was needed before recommendations could be made about how to reverse rising obesity rates.
The WHO commissioned research to explore the relationship between total fat intake and indicators of body fatness, including weight, waist circumference or Body Mass Index (BMI).
The researchers took the results from 33 high quality trials in western countries involving 73,589 participants. Data from 10 other studies were also included.
They then compared those on a reduced fat diet with others who had consumed their normal amount of fat.
After at least six months, participants had their body fat measured.
Weight loss and lower mortality
When data from all the trials was analysed, they found that those who swapped to low fat alternatives had lost an average of 1.6kg.
The report's authors say that although weight loss in individuals may be modest, it could have important implications in the population as a whole, leading to fewer deaths from some major diseases, such as diabetes, cancer, high blood pressure, heart disease and stroke.
For instance, more than 60% of adults in the UK have a BMI of more than 25. The researchers calculate that in a man of average height, weighing 80kg, that 1.6kg weight loss would reduce his BMI from 26.12 to 25.6, which would equate to a 3% reduction in the risk of dying.
Swapping high fat foods for low fat alternatives
It is easy for people to be confused about the impact of different types of fat in your diet. For instance, we are frequently reminded that using olive oil is better for us than butter.
The authors say that 'good' and 'bad' types of fat probably do not make much of a difference in terms of our weight, but cutting out the saturated fats will have the added benefit of helping reduce health problems like heart disease and stroke. "The type of fat we eat is also important," says Lee Hooper. "So what we're suggesting is that the way of attaining lower fat is to cut down on saturated fats and also processed fats."
She says the message that stands out from the results is that we should aim "not to diet but to keep eating sensibly and over time". In other words, that a pre-wedding crash diet will be no good unless it is maintained during the honeymoon and afterwards.
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