Fat is Back

Five years ago the general advice on diet was to eat a low fat diet both to lose weight and protect your heart. Last month a major review that has taken two years to complete and considered 16,000 studies, has concluded that low-carb, high fat diets are more effective for weight loss than the status quo advice to eat a low fat, low calorie diet, without cardiovascular risks.

In fact, the report concludes that a low carb diet is, if anything, good for your cardiovascular health, “…a greater increase in HDL cholesterol (“the good cholesterol”) without having any adverse affects on LDL cholesterol (“the bad cholesterol”)”. This applies to both the moderate low-carbohydrate intake of less than 40 percent of the total energy intake, as well as to the stricter low-carbohydrate diet, where carbohydrate intake is less than 20 percent of the total energy intake.

My GL diet falls in the category of a moderate low-carb diet. The rest is made up of fats, emphasising mono and polyunsaturated fats from fish more so than meat, and also vegetarian sources of protein. However, the low-carb, high fat diet that has become popular in Sweden emphasises more saturated fats from meat.

Fredrik Nyström, from the University of Linköping, who helped develop the guidance, recently told the local Swedish newspaper Corren that many of his colleagues had been sceptical about recommending a low carbohydrate, high fat diet. However, they changed their minds when they reviewed the scientific literature. “It feels great to have this scientific report and that the scepticism towards low carb diets among my colleagues has disappeared during the course of the work. When all recent scientific studies are lined up, the result is indisputable: our deep seated fear of fat is completely unfounded. You don’t get fat from fatty foods,” Nyström said.

If you are feeling troubled because, somewhere in your mind is the mantra that ‘fat makes you fat’ and ‘saturated fats are bad’, it is increasingly clear that it is sugar and carbs that more readily turn into body fat, and also into the fat, triglycerides, found in the arteries. So, it is true that fatty deposits are found in the arteries but they are more likely to have come from sugar than fat.

I don’t really emphasise fat in my diets but encourage some fats such as the ‘medium chain triglycerides (MCTs) in coconut, which is easier to burn than store, and mono-unsaturated fats in avocado and olive oil. Also, omega-3 fats in oily fish have always been a substantial part of my recommendations.

The more unsaturated a fat (mono being ‘one’ degree of unsaturation, poly being ‘many’) the more prone it is to damage at high temperature. Hence, you don’t want to deep fry foods in polyunsaturated fats. I ‘steam’ fry in a mono or saturated fat (butter, coconut butter or olive oil) by sautéing foods, then adding in a watery sauce (perhaps lemon juice, tamari and water) to finish the cooking process by steaming, which takes place at a lower temperature than frying, hence preserving nutrients and fats. I also get through a jar of tahini a month, but adding it to cooking at the very last minute so as not to damage the polyunsaturated fats.

However, burnt meat fat also generates toxic heterocyclic amines (HCAs) and polycyclic aromatic hydrocarbons (PAHs), so eating lots of fatty crispy meat may not be such good news either long-term.

By focusing on low-carb foods, not being fat phobic, and getting enough protein mainly from fish, white meat and vegetarian protein I think you have the best of both worlds.

The more extreme high fat, low carb diets, which really emphasise lots of high fat meats and dairy products and very low carbs do work for weight loss in the short-term but my concern still remains in their long-term effects. We don’t have long-term studies of these kind of ‘ketogenic’ diets but the long-term studies on diets high in red meat, processed meat and dairy products do consistently point to increased gastro-intestinal cancer risks. So this kind of high fat, low carb approach may be more acceptable short term, to reverse weight gain and diabetes, than a model for a perfect long term diet.

What we don’t really have enough of yet are comparisons in terms of health and weight loss between my kind of low GL diet (moderately low carbs but good ‘low GL’ ones and a bit more fat and protein) and very low carb/high fat diets. Those studies that have been done show comparative results. Both approaches are certainly more effective than the conventional low fat, low calorie diet – the mantra of old school dieticians.

Meat eaters will tend to favour the low carb, high fat (and meat) diets while vegetarians and ‘fishichickitarians’ will do well on my low GL diet, which has many other health foods and benefits built in. Here’s a posting on my Facebook page from a diabetic who tried it out.