Tag Archives: Ancel Keys

Constant thoughts of food? It could be linked to your diet.

One statement I hear regularly in my eating disorder clinics is “I feel like I’m going mad, all I think about is food”. Now whilst an eating disorder is a mental health illness it is not a sign of madness. However you can feel so consumed by your thoughts of food that it feel that way. Why? Well let’s have a look at some of the symptoms of being underweight….

Back in 1941 there was a landmark study conducted by Ancel Keys called the Minnesota experiment. The aim of this study was to get information on how to refeed those starving from famine conditions. 32 men completed the study, 12 of these were studied for 8 weeks to assess their baseline intake before the trial began. Then they were all starved for 24 weeks, with their intake reduced from 3,200kcals to just 1,600kcals/day served in 2 meals. which led to a 25% loss of body weight.  Now take a note of the number of calories, yes these men would have been more active and lived a different lifestyle but 1,600kcals led to them being starved. Many of the diets that are advertised today are much lower in calories that this, so are they really healthy for our bodies? 

Fascinatingly the men showed a lot of the symptoms we see in people suffered from an eating disorder. They become obsessed with food. Some read cookery book and stared at pictures of food. Cheating become a huge issue with them trying to find extra snacks. One man became psychotic, having vivid dreams of eating flesh and threatened to kill Keys, he was dismissed and after a few days these dreams and thoughts went away. This to me highlights the affect being a low weight can have on your thoughts and mental health. If you have an eating disorder and are a low weight that pre-occupation you have with food can totally be related to your body being undernourished. It is not you going loopy, it is the impact of being malnourished.

These men displayed a biological drive to eat, their hunger was increased and felt out of control. Keys ended up having to have each men chaperoned to stop them eating other snacks when not in the hospital. Our bodies are built to live and to live we need food. So they will do all they can to get us to eat. When you restrict your intake it makes perfect sense you will hungrier than before, stronger signals are being sent out and the body is going into amber alert. So that pre-occupation with food is actually a normal, biological sign that your body is working and doing it’s job.

The good news is, upon being re-fed, for most men, these symptoms disappeared. They were refer back to their usual weight and felt a lot better. Their thoughts, mood and emotional state improved alongside their physical healthy. Some of these men were interviewed in 2003 and they reported being glad they took part in the study, but there being some lingering after-effects. Some were worried about food deprivation for years afterwards. This can also be seen sometimes in recovery from an eating disorder, which is why  it is important to focus on recovery happening in stages and being a continual work in progress. 

If any of this has hit home to you and you feel like you need some support, do get in contact with me, see your GP for advice  or check out the B-eat website who have a helping and a list of eating disorder specialists. Taking that first step can be the hardest but with good support around you, recovery really is possible.

 

 

The low down on Fats. Are saturated fats really the villain?

Recently the world of fat had a shaking up. For 50 years saturated fat has been the bad guy, linked to coronary heart disease. But a systematic review and meta-analysis of the research looked at 32 worldwide cohort studies that reported finding a link between saturated fat (SFA) and coronary heart disease (CHD) and begged to differ.

Dietitian UK: Saturated Fats: The Lowdown

The original landmark research that led to the development of our dietary guidelines was done by Ancel Keys, the Seven Countries study in the 1970s. He found links between CHD and cholesterol levels and linked this to saturated fats as we know saturated fats increase cholesterol. However this was not actually proven and no research was done to then prove the association or to look at the impact of the dietary guidelines. 

The new analysis found that:

  • Saturated fat, omega 6 fatty acids, and monounsaturates (MUFA) were not linked to heart disease but instead they were neutrally related to the risk.
  • Trans fats were associated with a  16% increased risk of coronary events, a 34% increases in all cause mortality, 28% increase of CHD mortality and 21% increased in risk of CHD.  
  • Omega 3’s led to a reduced risk. 

The research analysed in these studies was carried out using diet history questionnaires and diet records and we know this is not always ultra-reliable. There is always the potential for bias and under/over-reporting. Different studies also used different views on fat categories so it confuses the results slightly.

What has happened: Some of the research looking at saturated fats compared extremes of intake. When you reduce saturated fats you increase polyunsaturated and monounsaturated fat, or you increase carbohydrates. The research often doesn’t tell us what foods were changed if saturated fat levels were altered.

What are Saturated Fats and how much should we eat?

The fats found in animal products: butter, cows milk,meat, salmon and egg yolks and in Plant products: chocolate, cocoa butter, palm oil. 

Dietary guidelines are that saturated fats should be limited to <10% and trans fats to <1% of energy. These still stand.

Fresh MeatWhat do you eat instead?

Research in 2005 showed us that replacing SFA with carbohydrates caused a small increased heart disease risk and instead should be replacing it with polyunsaturated fats (PUFA). Another study looks at the quality of carbohydrate, which I think is the key. It found replacing  SFA with high glycemic index carbs led to a higher risk.

If you replace saturated fats with high glycaemic index carbohydrates, the “bad LDL cholesterol” increases. There is a direct association between LDL cholesterol and heart disease mortality. What we replace saturated fats with is important.  Highly processed CHO are known not to be good for us due to their effect on blood sugars.

A 2% increase in energy from trans fats is associated with a 25% increase in risk of CHD and 3% increase in CHD mortality.  So we don’t want to be eating more of those. 

Current recommendations are that we replace SFA with PUFA and not with refined carbohydrates. So there is still am emphasis on lowering saturated fat but not going for very low fat diets. We all need some fats in our diet and very low fat diets are no longer recommended.

PUFA’s are found in:

High quality carbohydrates from fruit and veg and grains.

Nuts, seeds and plant oils.

Omega 3’s – 2 portions oily fish or vegetarian options such as linseed, hemp oil, walnuts and chia.

Dietitian UK: Healthy Fats

Can SFA’s be good for us?

Some foods that contain saturated fats also have other goods nutrients: vitamin A, D calcium and phosphorus are in dairy foods for example. Vitamin D is a nutrient that we are finding more people are deficient in so we do want people to be eating full fat dairy. 

It’s a complex relationship to understand. There are so many confounding factors when we look at diet and heart disease, you cannot control them all. 

We know now that dietary fats have different biological effects. Not all SFA’s behave in the same way. So it looks like excess lauric, myristic and palmitic acid are shown to decrease LDL cholesterol clearance which is not a good thing, but other length fatty acids are not associated with CVD risk. 

All saturated fats are nutrients with very specific functions, we metabolise them differently and synthesise fatty acids when we eat sugars, alcohol and starch. So SFA is not the only thing responsible for heart disease risk. 

 

 

It is more complex than we originally gave it credit for.

The concern is that is we remove one nutrient it gets replaced with something else  that may not be as good.

So it’s not all about reducing SFA but more key is what we replace it with. It’s not the cutting down that is always key but what we increase and actually eat more of. Perhaps our dietary guidelines should look at what to EAT MORE of rather than the negative EAT LESS. 

Individual changes to one nutrient have a knock on effect on another. WE want to see the bigger picture here and look at the balance of the whole diet. Maybe look at what you shold eat more of and not what to reduce. as you eat more fruit and ve you will eat less processed foods. 

 

References:

 

BMJ 2015;351:h3978 SFA meta-analysis

http://www.ncbi.nlm.nih.gov/pubmed/19211817

http://www.ncbi.nlm.nih.gov/pubmed/20375186 

The saturated Fat debate. Jenny Rosborough. Complete Nutrition Vol 7 (No2) June 2015