We all need fat to maintain healthy skin and for the metabolism of cholesterol. Although you need a PhD in biochemistry to understand the biological pathways used in its breakdown and synthesis. Fat is also needed to help form prostaglandins, which regulate the body’s response to injury and infection (we see it and feel its effect as inflammation). Prostaglandins also help in blood vessel contractions and nerve impulses.
The fat-soluble vitamins A, D, E, and K, stored in our body fat have many vital uses:
Vitamin A, also known as retinol, has several important functions.
These include:
- helping your body's natural defence against illness and infection (the immune system) work properly
- helping vision in dim light
- keeping skin and the lining of some parts of the body, such as the nose, to stay healthy
Vitamin D used to be thought essential, along with calcium, for teeth and bones. However as you may have read in my last post there is some ongoing research which disputes this long-held belief.
Vitamin E helps maintain healthy skin and eyes, and strengthen the immune system.
Vitamin K is needed for blood clotting, which means it helps wounds heal properly.
There's also some evidence vitamin K may help keep bones healthy.
So you see fat is necessary!
So you see fat is necessary!
And fat is a concentrated source of energy for the body; it provides us with 9 calories of energy per gram (compared with 4 calories per gram from either carbohydrates or protein). Also fat is an important calorie source, especially for infants and young children; 50 percent of the calories in human breast milk come from fat. Babies need the fat to grow but for the rest of us most fat, as we know only too well, is stored in the body’s fat cells, giving us an extra tyre or an unwanted bulge. On the positive side it’s good to know that fat deposits store energy and are also important in insulating the body, ie keeping us warm, and cushioning vital organs.
Fats are divided into 3 categories: saturated, monounsaturated, and polyunsaturated - depending on the amount of hydrogen they contain. The degree of saturation determines whether the fat is a solid or a liquid at room temperature. The basic unit of a fat is called a fatty acid. Fats with lots of saturated fatty acids (like butter and lard) are more solid at room temperature; oils (like olive oil) contain mostly unsaturated fatty acids and are liquid at room temperature. There is not space to look at all fat types here but see next week for more details and thoughts on the 'Good fat-bad fat' debate.
The fat in food is often referred to as saturated, monounsaturated or polyunsaturated, but none of the fats that interest us from a nutritional point of view is 100 percent saturated, monounsaturated or polyunsaturated. Olive oil contains 13 percent saturated fat, 72 percent monounsaturated fat, and 8 percent polyunsaturated fat. Because it contains more monounsaturated fat than anything else, it is classified as a monounsaturated fat.
Saturated fatty acids are usually solid at room temperature, and they’re more stable than other types of fats: they don’t go rancid especially fast. Saturated fatty acids raise blood cholesterol, especially the LDL ( low density lipoprotein) or “bad” cholesterol. Your risk of coronary heart disease rises as your blood cholesterol level increases. The fat in meat is considered mostly saturated. In the brave new world of vegan and vegetarian diets we are being urged to cut down on our consumption of red meat. The world can’t sustain its production.
BBC News this weekend stated ‘Just a week after scientists said huge cuts in carbon emissions were needed to protect the climate, a UK minister has shown just how hard that will be. Scientists say we ought to eat much less meat because the meat industry causes so many carbon emissions.’
It’s better for our bodies if we cut down on saturated fat, too.
Butter out of the fridge softens but doesn’t become completely runny —that’s because butter is saturated fat.
Trans fats are a subclass of saturated fat, but they started out as an unsaturated fat like vegetable oil. Food producers and snack makers add hydrogen to vegetable oils. Hence the term hydrogenated. Trans fatty acids also tend to raise LDL (“bad”) cholesterol and lower HDL (“good”) cholesterol. Saturated fats and trans fatty acids have given fat a bad name and are implicated in: heart disease, arteriosclerosis, cancer, high blood pressure, and diabetes. However, with a few changes to your diet, you can reduce the bad (saturated and trans fat), but still keep the good (and necessary!) mono-and polyunsaturated fats. Limiting saturated fats in your diet basically means avoiding high-fat red meats and whole-fat dairy products. Eliminating all the saturated fat in your diet isn’t necessary. Eating saturated fats in the right proportion with unsaturated fats —at least 2 to 1(unsaturated to saturated) —is good:
- Try to eat fish two times per week.
- Use olive oil.
- Eat more olives and avocados.
Michael Mosley’s 5:2 diet, coupled with HIIT* (high intensity interval training) is worth following. The science behind his recipes concurs with the low-sugar, low-LDL approach. However he and his team have found people who eat full-fat dairy, such as Fage 5% Greek yogurt, remain leaner and healthier than folk who choose low-fat yogurts and cheeses. The *HIIT helps raise our metabolism which in turn burns off the extra weight we, in the well-fed West, are carrying.
One food stuff all nutritionists appear to agree upon is the olive. Tuna,
another good food stuff, is even better if you buy it canned in olive oil.
So the bad boys are saturated and trans fats. What of the good guys?
Monounsaturated fats are liquid at room temperature. Olive oil is a monounsaturated fatty acid which lowers blood cholesterol. It lowers the LDL (“bad”) cholesterol, and increases the HDL (“good”) cholesterol (which is a good thing). Monounsaturateds also seem to lower triglycerides in some people when substituted for carbohydrate in the diet, according to doctors. Monounsaturated fats are liquid at room temperature.
These good fats come from almonds, avocados, cashews, olive oil, olives, peanut butter, peanuts, pecans and sesame seeds.
Omega-3 fatty acids are special polyunsaturated fatty acids. They are the super-good guys and help our bodies fight some of the worst modern-day killers: heart disease, stroke, and cancer. We know that omega-3 fatty acids lower LDL (“bad”) cholesterol and triglycerides. Omega three is found in fish and fish oils but can also be found in walnuts.
On triglycerides
In the human body, high levels of triglycerides in the bloodstream have been linked to atherosclerosis and the risk of heart disease and stroke. However, the relative negative impact of raised levels of triglycerides compared to that of LDL:HDL ratios is as yet unknown. The risk can be partly accounted for by a strong inverse relationship between triglyceride level and HDL-cholesterol level. But the risk is also due to high triglyceride levels increasing the quantity of small, dense LDL particles.
Raised triglycerides often go hand in hand with low HDL level. HDL levels are the ones you want to keep high!
Michael Mosley, he off the tele in 'Trust Me, I'm a Doctor' gives the following advice for a heath-giving weekly diet. It includes the following general (low-refined-carb, higher fat) tips:
- Eat 2 – 3 servings of full-fat yogurt a week.
- Choose eggs for breakfast at least twice a week.
- Embrace a variety of vegetables - see my earlier post on the benefits of phytochemicals and fibre.
- Have at least one serving of salmon per week.
- Add at least one other fish or seafood during the week - remembering the super-good guys - omega three!
- Avoid consuming grains / legumes consecutively (ie. lunch then dinner).
- Have approximately two meals of chicken a week. It’s high in protein.
- Go easy on red meat or cut it out completely.
- Enjoy vegetarian foods - which can include fish and eggs. At least two meals is a guide, more if you feel like it.
- Aim for approximately 800 calories on your 5:2 or 4:3 fasting days. Mosley’s research shows that if the body thinks it’s going to starve it helps reduce weight. 800 calories doesn’t seem much but see below.
1. Always take the stairs. Incidental exercise like this helps keep us fit and adds to the advised magic number of 10,000 steps we are meant to take daily.
2. Avoid FIZZY DRINKS and SOFT DRINKS. Stick to WATER or SODA WATER. Soda water is calorie-free.
3. Don't snack between meals - snack bars often contain high levels of added sugar.
4. Don't keep pasta or milk chocolate in the house. Two squares of low-sugar, high-cocoa chocolate are good for an evening treat however.
5. When you can, walk.
6. Always chose the full fat option. You won’t get Mosley to agree with nutritionists who claim low-fat butter, yogurt or cheese is the way to go.
7. Avoid breakfast cereals (apart from porridge) as they contain high levels of added sugar. Steel-cut porridge fills you up longer and it's a whole food (see an earlier post of mine re: whole foods v processed.)
8. Occasionally give in to temptation (for example, having dessert if you are dining out for a special occasion) and high-cocoa chocolate is advised.
9. Practise mindfulness for at least 10 minutes every day. Relaxation has been shown to help reduce extra fat we are carrying. Stress helps us lay down unwanted fats.
10. Stand on the scales everyday. This way you can do a few more steps or do another fasting day to lose those added pounds before they settle around your vital organs as visceral fat.
A typical 800 calorie day for me might be
Breakfast
50g whole porridge oats with blueberries.
As much water as I like to stop dehydration and headaches. Drinks of Green & Blacks cocoa keep hunger at bay on fasting days.
Lunch
Home-made carrot soup now we are well into autumn. On warm days I prefer salad:
Half a can of tuna in olive oil.
Home-grown baby spinach leaves.
Home-grown cherry tomatoes (about 5).
Grated carrot.
A handful of olives.
Sprinkled nuts, sesame seed or pomegranate on top.
If I feel hungry later I chop a large carrot into sticks and stay satiated that way. But I don’t reach into the cookie jar.
Evening meal. I try to eat before 7:30pm.
A small cut of chicken breast, flavoured with harissa. (See a previous post for full details).
Home-grown French beans.
Six shoots of asparagus.
No potato!!
If I haven’t had tuna for lunch I substitute a salmon fillet for chicken.
For afters
3 tablespoons Fage 5% Greek yogurt favoured with blueberries.
At bedtime, when you might find you feel a gnawing hunger on fasting days, it’s good to have a drink of fruit tea. It contains no calories and helps you feel full and get to sleep - or nibble on a carrot.
The 800 calories above contain phytochemicals in the vegetables and berries, omega three in the fish, good fats in the olive oil and yogurt. Protein is in the chicken. Cheese can be substituted for tuna and, again, it helps you feel full on fasting days. And good carbohydrate, which avoids sugar spikes, is in the porridge oats.
Next time: Good fat, bad fats - part II.
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