The old ‘calorie myth’ stated that a calorie is a calorie is a calorie – it doesn’t matter whether you eat a 100 calories (or kilojoules) of lollies or broccoli, they will have the same effect on your weight. Yes, all “calories” do have the same amount of energy, but when it comes to your body, things are not that simple.
Read on to find out how our body’s biochemistry treats different foods differently and how, in many cases, simple changes in food selection can lead to the same (or better) results than calorie restriction.
Simply putting your focus on eating fewer calories than you burn is a losing strategy, because this oversimplified numerical approach treats all calories as equal — which they are not, says David Ludwig, MD, PhD, a Harvard Medical School professor and internationally respected obesity researcher. It’s not so much the quantity of calories we eat that drives weight gain and loss, he asserts, but rather the nature and quality of those calories.
6 Reasons why a calorie is not a calorie
1. Proteins and thermogenesis
It is very clear that when it comes to metabolism and appetite regulation, a protein calorie is NOT the same as a carb calorie or a fat calorie.
Because the human body is a highly complex biochemical system with elaborate ways of regulating energy balance, different foods go through different metabolic pathways. Some of these are more “efficient” (that is the more of the food energy is used for work and less lost as heat) than others.
The metabolic pathways for protein (found in foods such as meat, fish, chicken, eggs, milk, cheese and yoghurt, soy , grains (quinoa, oats, barley…) nuts and pulses (dried beans, peas and lentils) are less efficient than the metabolic pathways for carbs and fat. What that means is that the body uses much more energy to break down protein than fats and carbs, which means protein in a meal assists in burning up more calories.
More good news about protein – it significantly reduces appetite, making you eat less calories without even having to think about it.
So adding more protein to your diet may be one of the best ways to cause “automatic” weight loss. In light of this I recommend GOOD QUALITY protein at every meal.
In one study, those who increased their protein intake to 30% of calories automatically started eating 441 fewer calories per day and lost 4.9 kg (11 lbs) in 12 weeks.
What about satiety?
It is much easier to overeat on some foods than others and this depends on the satiety index – a measure of the ability of foods to reduce hunger, increase feelings of fullness and reduce energy intake for the next few hours.
For example, it may be quite easy to eat 500 calories (or more) of ice cream or cheesecake, while you’d have to force feed yourself to eat 500 calories of eggs or broccoli.
Many factors determine the satiety value of different foods (from fibre content, glycaemic index and so forth), but this is a key example of how the food choices you make can have a huge impact on the total calories you end up consuming.
3. Real foods vs processed foods
The foods we eat can have a huge impact on the biological processes that govern when, what and how much we eat.
Whole foods also require more energy to digest than processed foods
A study compared two sandwiches that had the same number of calories and macronutrients; one sandwich was made with whole grains and cheddar cheese, while the other was made with refined grains and processed cheese. Those who ate the wholegrain sandwich burned twice as many calories digesting the meal.
We require a consistent balance of healthy macro-nutrients (protein, fat, and carbohydrates), micronutrients (vitamins, minerals, antioxidants, phytochemicals), and adequate phytonutrients, enzymes, fibre, water, to function. When we are missing these elements, our energy levels drop, our hormones and neurotransmitters get imbalanced, and our metabolism stops working efficiently. Our vitality suffers, and our bodies don’t regulate much of anything (including our weight and body composition) as they are designed to.
This is why replacing whole foods with foods selected exclusively because they are low-calorie, low-carb, high-protein, or low-fat may work against long-term weight loss.
A varied, whole-foods diet will also naturally offer a relatively low glycaemic load (GL) and a high phytonutrient index (PI).
A low-GL meal slows the rate at which carbs turn to sugar in the bloodstream. And this slow burn allows your body to digest sugars without triggering the metabolic signals that promote hunger and weight gain. Phytonutrients, meanwhile, are powerful healing agents and metabolic regulators necessary to the body.
To make the most of the calories you ingest, emphasize foods with a low GL and high PI, including vegetables, fruits, beans, nuts, seeds, olive oil, whole-kernel grains, teas, herbs, and spices. Say no to diet plans that emphasise caloric quantity over nutrient quality.
4. Fructose vs Glucose
The two main simple sugars in the diet are glucose (commonly called sugar) and fructose (found in fruits, honey and some vegetables). Whilst they seem almost identical with the same weight and formula fructose has different effect on the body
· Glucose can be metabolised (broken down in this case) by all of the body’s tissues, but fructose can only be metabolized by the liver in any significant amount.
· When our body is flooded with fructose the “hunger hormone” Ghrelin goes up leading to a greater appetite and energy intake than glucose.
· Fructose fails to stimulate the satiety centre in the brain in the same way as glucose, and so we still feel hungry after eating fructose rich foods.
· The most damaging effects of fructose is the decline in liver function which may lead to insulin resistance, abdominal fat gain, increased triglycerides, blood sugar and small, dense LDL (‘bad’ cholesterol) compared to the exact same number of calories from glucose.
Remember this applies to fructose from added sugars only and not from fruit, because they also have fibre, water and significant chewing resistance, which mitigate the negative effects of the fructose (unless you eat an awful lot!!!). Saying that one to two pieces of whole fruit a day is plenty.
5. Low-Carb (not NO carbs) lead to less calorie consumption
Studies consistently show that low-carb diets lead to as much as 2 – 3 times as much weight loss.
One of the main reasons for this is that low-carb diets lead to drastically reduced appetite. Another reason is that low-carb diets tend to include more protein than low-fat diets. Protein takes energy to metabolise and the body expends energy turning protein into glucose.
There are many controversies in nutrition and the experts don’t agree on many things. But one of the few things that almost everyone agrees that refined carbs are bad. This includes added sugars like sucrose and high fructose, as well as refined grain products like white bread.
Refined carbohydrates tend to be low in fibre and they get digested and absorbed quickly, leading to rapid spikes in blood sugar. They have a high glycaemic index (GI), which is a measure of how quickly foods raise blood sugar.
When we eat a food that spikes blood sugar fast, it tends to lead to a crash in blood sugar a few hours later… also known as the “blood sugar roller coaster.” When blood sugar crashes, we get cravings for another high-carb snack.
In one study that served people milkshakes who were identical in every respect except that one had high GI carbs while the other had low GI carbs, the high GI milkshake caused increased hunger and cravings compared to the low GI shake.
Another study found that teenage boys ate 81% more calories during a high GI meal compared to a low GI meal.
So… the speed at which carb calories hit the system can have a dramatic effect on their potential to cause overeating and weight gain.
Check out Glycaemic index to find out more
So what can we take from all this?
· Different calorie sources can have vastly different effects on hunger, hormones, energy expenditure and the brain regions that control food intake.
· Even though calories are important, counting them or even being consciously aware of them is not at all necessary to lose weight.
· In many cases, simple changes in food selection can lead to the same (or better) results than calorie restriction. Increasing protein, eating foods with a high satiety index that fill you up for longer, and eating a diet of wholefoods would be a really good start.
Whether you need to lose weight of not – these principles are important for everyone’s health and wellness.
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