Does fat make you fat?

If you take a look at the current dietary advice on weight loss, you are likely to read a contradictory mixed bag of information. Some "experts"* advise you to cut out all fat, whereas other "experts" advise that fat speeds up fat loss.

Looking at all the scientific studies, it is clear that fat is a crucial substance which we need in order to be healthy and that specific fats are important for healthy metabolism. Essential fatty acids found in fats and oils are recommended by doctors and nutritionists for many good scientific reasons. However, there is clear evidence that we need to monitor our fat intake because too much fat is implicated in obesity. So how much fat is healthy? Is fat addictive? How can we enjoy our food while eating less fat? All these questions are answered in this article.

Why is fat important?

Fats and oils occur naturally in meat, poultry, oily fish, dairy, grains, seeds, and nuts. Fats and oils are needed for many processes in the body. They insulate us from the cold, and keep our skin soft and supple. They are crucial for the functioning of the brain and the hormones and they play a vital role controlling inflammation and pain. They are very important for maintaining the membranes of cells and allow the absorption of certain vitamins. Fats can also be used by a body as a source of fuel. Certain components of fats and oils, called fatty acids, are also crucial for health. Omega 3 fatty acids are proving very important in the prevention and management of diseases including certain cancers, immune disorders and circulatory and cardiac disease.

Fats are also because they make food tasty. A very low diet (15% or less) is unpalatable to most people.

So how much fat should we include in our diet?

We are advised to consume about 20 to 25% of our daily energy intake, from fats and oils. The average Westerner consumes a lot of fat, around 40% of daily calories. Most of the foods that we eat contain some fats and then we add more to our food via frying, salad dressings, spreads and so on. Processed food is often high in fat, as well as sugar and salt.

What's the problem with fats in terms of weight management?

It may be difficult to effectively control our intake of fat for a number of reasons and this may lead to fat gain. Firstly, the fat content which we evolved with is much lower than the amount we now consume.

Modern humans consume a lot of extruded oils which have been pressed or refined from plants and then put into bottles and these oils are obviously 100% fat. The oil is also used to make margarine and spreads which are about 80% fat. Margarine is barely 100 years old as a food. It took some time for the chemists to be able to make the substance attractive enough for people to choose it over butter.

In nature, to get the oil, we have to eat the whole food. Think of 15 gram tablespoon of olive oil. This contains the same amount of oil as 27 medium olives. To consume 15g of corn oil you would have to eat over 1 ¾ pounds of sweetcorn!

There is evidence that our bodies have not developed the regulatory mechanisms deal with this amount of oil, so we are unable to control our intake of fat intuitively. Our satiety hormones don’t kick in as they do with protein. Hence, it is possible to consume a lot of extra calories eating foods high in fat, before the body’s satiety mechanism switches on.

Secondly, not all foods are equal in terms of how our body processes them and uses them as energy. Fats are utilised and stored very efficiently. The energy in food is measured in calories, a calorie being the body’s energy currency. If we take the calories contained in the same weight of food, we learn that fat contains 9 calories per gram, whereas protein and carbohydrate are less than half the calories at 4 calories per gram. So in terms of volume, we can eat twice as much weight of protein and carbohydrates as fats for the same number of calories.

Then there is what is known as the “thermic effect” of food. Every time we eat, it costs calories to utilise or store that food. Fats, carbohydrates and proteins use different amounts of energy in this process. When you eat 100 calories of fat, it costs just 3% of its calories of energy to metabolise that fat. The thermic effect of carbohydrate is 20%. Processing protein requires the greatest amount of energy – up to 30% of its energy is used to metabolise it. So while 100 calories of fat would take just 3 calories to process, that same 100 calories of protein would take 30 calories to process.

So looking at fat positively, you might say that it is a high energy, easily utilised, and energy efficient fuel for the body!

Is it possible to have an addiction to fatty foods?

The third reason why fatty foods may be fattening is the effect that they exert over the biochemistry and neurochemistry of the body.

One experiment looking at the “cafeteria diet” published in the American Journal of Nutrition in 1995 also supported the hypothesis that fat makes you fat. Women were allowed to eat freely from a selection of cafeteria foods and the ones who ate the higher fat foods got the fattest.

In 2001, the International Journal of Obesity Related Metabolic Disorders also found that when offered a choice of foods, rats prefer high-fat and/or high-sugar food items over their nutritionally balanced normal rat diet. In addition, they may overeat by 20-40% calories and develop obesity.

High fat diets may also not help you to exercise or think, both skills which are handy when getting fit and trim! In 2009, Oxford University researchers showed that rats fed a high-fat diet show a stark reduction in their physical endurance and a decline in their cognitive ability after just nine days,

A recent study by Departments of Pharmacology and Biological Chemistry, University of California also demonstrates that it is likely that fatty food is “addictive” if. It may explain why it is very difficult for the average person to eat a handful of crisps or a few chips and why we can overeat fatty food beyond normal levels. In this study, it was found that fatty foods produced endocannabinoids (cannabis-like compounds produced in the body). The endocannabinoids are known to play an important role in regulating ‘rewarding’ feeding behaviours. Se we feel good when we eat fatty foods because our bodies are stimulated to produce these chemicals and this the leads to overeating and reinforcement of eating fatty foods.

Why do we have this mechanism?

Before we humans started farming, (which isn't very long ago in our human evolution, a mere 12,000 years), we would have eaten a variety of plants, seeds, nuts and animals specific to the area in which we lived. These contained fats and oils in small amounts. The animals that we hunted were relatively lean compared to farmed animals of today. Fat may have been a luxury not encountered in quantity very often.

It may be that because fat wasn't so readily available and yet such a valuable resource, the human body evolved mechanisms that made us overeat fat when it was available, so that we were able to store this material for future energy needs and insulation of vital organs in a harsh climate and environment. I am a great believer in the marvellous design of the human body, so although the ability to store fat in the present time may seem a distinct annoyance or disadvantage, in previous history it was a useful adaptation for survival!

How to control fat intake

The easiest way to achieve a healthy level of fats and oils is to avoid processed food which can have a lot of added fat in order to make it more palatable and to improve the appearance and texture of the it. If you cook all your food from fresh, remove all visible fat and are conservative with dressings and cooking oils, you will be reducing your energy intake from fat significantly.

It is easier to control your nutritional intake and eating habits, by eating fresh food and preparing your own meals and snacks so that you know what's in them. You will also want to think of some good strategies so that you are psychologically prepared to respond to high-fat foods when out of your safe food environment. Going supermarket shopping, going out for a meal or visiting friends may mean being presented with high-fat foods, and having pre-thought responses prepared for those and other common events means that you can make better food choices.

Some fans of the high protein low carbohydrate diet advise eating nuts. Nuts are great but they are very high in fat. Can you eat a few? If you can great. If you tend to eat bags of them they will make you fat. A small bag of peanuts containing 50 grams of nuts, has nearly 300 calories, most of those from the 25 grams of fat (that is 5 teaspoons of fat! Remember, a teaspoon contains about 5 grams of liquid).

It may be helpful to keep any high-fat snack type food out of the home, certainly if you have a relationship with that food that means that you don't feel in control of your consumption of it. Then you can decide when you want to enjoy a high-fat snack in an appropriate and controllable setting. You might decide to not have crisps and chips in the house, but to enjoy a small portion of those at certain times. This could also be very beneficial for any children you have the care of, if you want to help them to nurture long-term behaviours that will lead to health and longevity.

If you have become used to over eating fatty food, there may be a transition in adapting to cooking and eating lower levels of fat. As you learn how to prepare meals with a healthy fat percentage and to adapt favourite recipes, you will have successes and disappointments. So remember to be supportive and nurturing during this time and focus positively on the changes you are making. It is as a process, a journey, so let go of perfectionism and enjoy your discoveries and increased health.

I often help my clients to create new recipes or adapt favourite recipes as part of the coaching process. I am a great cook as well as a nutritional therapist, so I love to educate people about food, and the amazing beneficial chemicals in foods as well as to help them get pleasure from what they eat and freedom from the horrid diet demons.

If you would like to review the beneficial effects of essential fats and how to strike a balance, read this short and important article on EFAs.