“Fat makes you fat”. Sounds plausible, doesn’t it?
It was the mantra of the low-fat diet craze which first found favour in the 1980s, and blazed a trail through the diet industry for much of the 1990s. Even now, the “logic” of this statement is firmly embedded in the consciousness of many. Entire countries have been known to form nutritional policy on its basis – most recently, the Danish government, who introduced a fat tax. There are rumours that other countries might follow suit.
But the truth is – fat doesn’t make you fat; not inherently, anyway. And – more sacrilege! – saturated fat doesn’t clog up your arteries. I know from my own experience that eating a diet rich in appropriate fats has actually enabled me to maintain a healthy weight without having to flog myself half to death in a gym – and I used to be a devoted low-fat foodie. But don’t just take my word for it – science confirms what many of us have already discovered.
Evidence That Fat Isn’t Fattening
The notion that fat may not be inherently fattening received support from a fairly recent study which looked at the relationship between dietary fat levels in almost 90,000 European adults and changes in their body weight. The study subjects were followed for several years.
The authors found no association between total fat intake (or intake of any specific type of fat – monounsaturated, polyunsaturated, saturated) and weight change. They concluded:
We found no significant association between the amount or type of dietary fat and subsequent weight change in this large prospective study. These findings do not support the use of low-fat diets to prevent weight gain.
A study the year before, by the respected Cochrane Collaboration, indicated that individuals following a low-fat diet as a means of controlling weight were unlikely to succeed in the long-term.
Further, a major review conducted at the Harvard School of Public Health indicated that dietary fat was not a major determinant of bodily fat.
Fat Doesn’t Clog Your Arteries
Obesity researcher Zoe Harcombe provides a most eloquent explanation of the truth behind “hardening of the arteries” and the myth that the culprit is healthy dietary fat:
Fat and water don’t mix so, since blood is effectively water, fat cannot travel freely around the blood system. Fat travels around in lipoproteins… The idea that fat somehow leaps out of the lipoproteins to attach itself to the arterial wall to try to clog up the system and kill us is ludicrous. The far more likely explanation for narrowing of the arteries is that the wall of the arteries suffers damage such that a ‘lesion’ or ‘scab’ forms. The body does not risk the scab breaking away– as this could cause a blockage. The lining of the wall tries to repair itself and forms a new layer over the scab – sucking the scab back into the lining of the artery wall in so doing. The trouble is – if we continue to be exposed to whatever was damaging the lining of the arteries (suspects are smoking, processed food, pollution, stress) – we continue to form lesions. We only need too many ‘scabs’ in one area, and the repair kit being unable to keep up, and we could be in trouble – big heart attack or stroke kind of trouble.
This brings us on to the ‘repair kit’. The best repair nutrient of all – the body’s chief anti-oxidant, anti-blood-clotter and repairer of blood vessels is vitamin E. Another trouble is – vitamin E is a fat soluble vitamin, found in nature’s real fat foods (meat, fish, eggs etc), which we are continually telling people to avoid! Another huge irony is that cholesterol and fat are the two main repair substances in the body. So, a lesion forms and cholesterol will head to the area to do its repair job and to try to fix the scab. Then, if the person dies because there’s only so much cholesterol can do, pathologists find cholesterol around the scab – at the scene of the crime so to speak – and blame cholesterol for causing the damage. How unfair is that? Police are always at the scene of the crime, but no one accuses the police of committing all the crimes…
So What’s The Real Problem?
If fat doesn’t make you fat – what does? It’s important to realise there’s no simple answer to this, and a host of factors – genetics, metabolism, stress levels, heredity, lifestyle – all play a part. But as Gary Taubes outlined in his book Why We Get Fat (And What To Do About It), the idea that fatty accumulation is caused by the “usual suspects” – too many calories, too much dietary fat – is just plain wrong.
The real picture is somewhat more sophisticated. Dr John Briffa provides a clear explanation:
Fat is stored in fat cells as substances called triglycerides. Triglyceride is made from substances known as free fatty acids. It takes 3 fatty acids and one molecule of a substance known as glycerol to make triglyceride. The free fatty acids are absorbed from the bloodstream into the fat cells. They can flow out again too. What ‘fixes’ them in the fat cells is their conversion to triglycerides.
The conversion of free fatty acids to triglyceride is dependent on the supply of a substance called alpha glycerol phosphate. This is produced when glucose is metabolised in the cell. In other words, the more glucose that gets into the fat cells, the more fat will tend to get fixed there.
For most people glucose comes from sugars and starches (carbohydrates) in the diet. But to get into the cells it requires the action of the hormone insulin. So, dietary carbohydrate supplies the glucose necessary for the manufacture of triglycerides, and also stimulate the secretion of insulin which gets the sugar into the cells. Insulin also stimulates triglyceride formation through its action on other hormones (lipoprotein lipase, glycerol phosphate acyltransferase and hormone sensitive lipase).
In short, what this means is that carbohydrate and insulin will tend to cause the accumulation of fat in the cells.
One important point of note: understanding these facts doesn’t mean that there’s a single dietary approach that will suit everyone. There’s no doubt that some people can eat relatively higher-carbohydrate diets and maintain a healthy weight or even lose weight. However, taken as a whole, the evidence shows three key things:
- Lower carb diets generally outperform lower fat diets for weight loss
- Lower carb diets generally outperform lower fat diets for biochemical markers of health
- Lower fat diets are generally less effective for weight loss in the long-term
The Paleo Diet Solution
As so many of us are discovering, the key to achieving and sustaining fat loss is by carefully controlling carbohydrate intake (and thus insulin production) within a balanced, nutrient-dense diet, such as the paleo diet. Does this mean we can run wild and gorge ourselves on any kinds of the fatty foods we like? Zoe Harcombe again:
When will we see the most obvious fact of modern life and modern illness? Man-made things are harming us and nature’s natural things have always been there to help us. The more we have of the former and the less we have of the latter, the more ill health we risk.
Good fats are those made by nature; bad fats are those made by man – that’s all we need to know.
Now that you know that fat doesn’t make you fat, please make the most of these Paleo Diet News resources – and pass the butter!
- Getting over your fat phobia
- The real causes of obesity
- In praise of animal fat
- Some fats you should be eating
- How to lose weight with the Paleo Diet
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