Salmon steak
Fish like salmon are high in Omega 3 oils iStock

The wrong balance of omega-3 and omega-6 in our diets is driving obesity more than calorie consumption, scientists based in the US have said.

Keeping a healthy weight isn't as simple as balancing the energy you consume in food with the amount you spend through exercise, say Artemis Simopoulos of the Center for Genetics, Nutrition and Health and James DiNicolantonio of Saint Luke's Mid America Heart Institute, both based in the US.

Too much focus on calorie consumption and overall fat intake is a distraction from the real problem of the balance of omega oils in our diets, they argue in an editorial in the journal Open Heart. If we want to tackle obesity, we should focus less on how much we consume, and more on the balance of omega-3 and omega-6, they say.

The typical western diet is skewed to include far too much omega-6 for the amount of omega-3 that we consume, the authors say. The recommended healthy balance is for Omega-3 intake to be not more than double the omega-6 intake. In reality, we consume about 16 times more omega-3 than omega-6.

This imbalance is new in human history. Eating a lot of red meat is one of the main foods that can drive omega-6 intake through the roof. But even the content of omega-6 in meat has been rising over the past century due to changes in farming methods, the authors say. Livestock is often fed on corn and other grains, which is high in omega-6, rather than grass, which is lower in it. This boosts the omega-6 content in the meat, eggs and dairy products that we eat compared with our ancestors.

DiNicolantonio told IBTimes UK that changes in diet over the past 100 years had more of an effect than changes in farming methods. "The biggest culprit would be diet, in particular, the introduction of industrial seed oils, also known as vegetable oils. Their intake went from basically zero in the early 1900s to over 40 pounds per person per year."

This balance should be brought back into line by eating less meat and oils high in omega-6, such as corn oil and sunflower oil. Omega-3 intake can be boosted by eating more oily fish and leafy vegetables.

Obesity levels have more than doubled since 1980, according to the World Health Organization. Simopoulos and DiNicolantonio say that as well as individuals choosing to rebalance the omega oils in their diet, policymakers should also step in to refocus the obesity debate to include omega oils as well as calorie intake.

Governments should alter their policies on tackling obesity to reflect this research, the authors say. Seed oils are a particular problem. "If we want to truly improve the health of the population and reduce health care costs, removing these seed oils would be a step in the right direction," DiNicolantonio said.

"It is the responsibility of governments and international organisations to establish nutrition policies based on science and not continue along the same path of focusing exclusively on calories and energy expenditure, which has failed miserably over the past 30 years," he continued.