“Food is all those substances which, submitted to the action of the stomach, can be assimilated or changed into life by digestion, and can thus repair the losses that the human body suffers through the act of living.” – The Physiology of Taste by Jean Brillat-Savarin
Many diet and fitness programs insist on eating raw, whole, fresh foods but it is not always made clear or obvious for everyone why eating whole foods as opposed to processed ones, is beneficial or even necessary. I will try to make this explanation as simple & sensible as possible, based on my understanding and personal experiences.
Our body requires food in order to obtain nutrients and energy that are vital for sustenance. There are two types of food: whole foods and processed foods. Whole foods are in their most natural form such as fresh vegetables, fruit, fish and meat—foods found in the typical ‘Paleo’ diet. Whole grains—grains such as wheat, quinoa, millet, etc.—are only considered in their “whole” form when they are eaten after being cooked with their hull on. Processed foods, as their name implies, have already been manipulated and although processed foods have energy and nutrients (although not nearly as much as whole foods, in proportion), and as such, they leave our body with very little work to do, which contributes to a host of problems, includingdiabetes, heart disease, high levels of inflammation, metabolic syndromes and a sluggish metabolism (for more info on what metabolism is and how to improve it, check out my article How to REV-UP your Metabolism! ). A number of studies have shown that disease rates are exponentially increasing in third world countries, such as Brazil and Guatemala, because these populations are increasingly consuming highly processed foods.
Let’s begin with understanding the thermic effect of food, which is the number of calories required to break down food, produce enzymes and get nutrients where they need to be in the body. Protein burns the most calories because it requires so many enzymes to break down, followed by carbohydrates and then fats, which burn the least calories. A fascinating study in the Journal of Food and Nutrition Research found dramatic differences in the thermic effect of whole food meals compared to a processed food meals. Researchers compared a processed cheese sandwich meal (processed cheese product and white bread) with a whole food cheese sandwich (whole grain bread with sunflower seeds and cheddar cheese). Both meals contained the same amount of calories and a similar proportion of carbohydrates, protein and fat. The thermic effect of the whole food sandwich was almost double that of the processed food sandwich—participants burned 50 percent more calories after eating whole foods! Equally significant is the fact that the participants who ate the processed food meal had their metabolic rates drop below their average resting metabolic rate (RMR)—the average energy needed to keep the body functioning at rest—during the sixth hour after eating, while the whole food meal group never fell below the RMR. Also, the amount of time required for the body to digest the whole food meal lasted an hour longer than the processed food meal, which also contributed to the greater amount of calories burned. Researchers note that the ingredients used for the whole food meal did require some food refinement and processing to produce, but not nearly as much as for the processed ingredients. They suggest eating a stricter whole foods diet to increase the thermic effect even more.
Furthermore, processed foods contain less fiber and often have added sugar and/or salt (which is why they take so long to spoil and last forever), making them detrimental to insulin health and the management of blood sugar. The high consumption of processed foods is a major factor which contributes to the increasing rates of diabetes because the low fiber content often makes food higher glycemic, meaning they raise blood sugar and insulin very quickly. This causes two problems: First the cells become resistant to the insulin, which leads to low energy and fat gain. Second, blood sugar spikes quickly and then drops very rapidly, which has been shown to result in people feeling hungry again and eating more—then they take in excess, often empty, calories and gain fat. As such, one of the first studies examining the difference between processed and whole foods shows how damaging processed foods are for metabolism and body composition. This study compared the insulin and glucose responses to two processed and two whole food snacks: A candy bar, soda with chips, raisins and peanuts, or bananas and peanuts. Calorie and macronutrient content were similar in all the snacks. The processed snacks had added sugar, but the total amount of carbohydrates from sugar were similar in the four snacks. Results showed that insulin was 70 percent higher in response to the processed foods than the raisin-peanut snack. The banana-peanut snack produced an intermediate insulin response that was still lower than the processed foods. Also, blood glucose peaked faster and dropped quicker in response to the processed food snacks than the fruit and peanut snacks. If you consider the dangerous insulin response to processed foods and the lower thermic effect, you will probably think twice before taking a bite from packaged or processed food again!
Research also demonstrates that individuals who consume more whole foods burn more calories than individuals who are more processed foods. A recent study in Journal of Nutrition found that older women who ate a diet with all their grains coming from whole grains while on a 12-week restricted calorie diet lost more total fat and more belly fat than women who ate the same diet but with all their grains coming from refined grains. Whole grain foods have more fiber than refined grain foods such as white bread or pasta and foods with more fiber are more slowly digested so that they have a more gradual effect on blood sugar regulation. In addition, the body uses much more energy digesting whole grain foods than refined foods.
Thus, a simple way to lose fat and make sure you are avoiding processed foods is to eat more foods in their raw form. Eating a greater variety of raw fruits and vegetables will also mean you are naturally getting more antioxidants, vitamins and fiber in your diet. Even more exciting, if you want to lose fat, eating raw food will decrease your energy intake because simple act of cooking food will significantly increases the amount of calories available to us. Research shows that cooking food “pre-digests” it and many of the compounds that increase the thermic effect are broken down, resulting in less energy expenditure from digesting cooked food. There is also less water in cooked food, making it more energy dense. For example, a Harvard University study that fed rats either cooked or raw sweet potatoes and beef showed that the rats that ate raw meals lost weight, whereas those that were fed cooked meals gained weight. This is supported by studies that show people who eat mostly or all raw diets have significantly less body fat than those who eat more cooked foods.
There is also abundant evidence that if you avoid processed foods and the chemicals they contain, you can prevent cancer and disease (more specifically, heart disease, diabetes and chronic inflammatory diseases). Eating whole foods provides a host of protective nutrients already mentioned (fiber, antioxidants, vitamins and minerals). Many studies published recently demonstrate that regularly eating processed foods, especially processed meat, was robustly linked with risk of cancer of the esophagus and stomach.
My favorite reason for eating whole fresh foods is because I have found that when I eat this way I tend to feel happier, have a better mood, and be more energetic, productive and optimistic. Two studies in the British Journal of Psychiatry show that eating a whole foods diet with vegetables, fruit, meat, fish and whole grains is linked to less depression than a typical Western diet of processed foods. Processed chocolate, meat, sweets made from refined grains like donuts and cake, cereal, dairy with sugar and chemicals added to it, and fried food were all linked with higher rates of diagnosed depression. Researchers suggest whole food diets prevent depression because people who eat whole foods diets get more vitamins, minerals, and antioxidants, have healthier guts, and have a better hormone response to eating. As such, the type of food you eat has a dramatic effect on your levels of brain transmitters, which dictate mood and energy levels as well as feelings, such as those of hunger.
Want to know my other reason for eating fresh? You can eat a lot more whole foods than you can processed foods, in terms of the mass volume, for the same amount of calories or less. A cup of grapes equals 60 calories whereas a cup of raisins is 300+ calories. Enough said.
Although I am in no way suggesting that you totally abstain from eating processed foods, if you are concerned about your body composition, long-term health, and repairing the losses that your body suffers during training and life, I suggest that you limit these foods despite the fact that they are convenient, cheap, easy to access, etc… Furthermore, it is important to note that not all processing is bad, such as in the case of skim milk where fat is stripped away or similarly in the case of lactose free milk. That said, I am undecided on whether milk is even a beneficial food in the human diet. I have been a vegetarian since I was 8 and was vegan for over 2 years of my life, during which time I obviously abstained from milk, and I found that during this time I had almost no mucus/phlegm, barely got sick, had extremely high energy levels, rarely had an upset stomach, had the clearest skin of my life and various other positive health-related outcomes. I am currently preparing myself to go vegan, and this time I plan on remaining vegan for the rest of my life. I am in the process of creating and re-creating vegan recipes and will post these as I develop them 🙂
Hope this article was helpful and clear. Happy healthy eating to you all 🙂