The theory of “calories in, calories out” gained popularity over the last 30 years and made us forget about earlier research that distinguished different types of nutrients and their effects on weight gain. The modern theory that a calorie is a calorie equates the body to a simple machine, ignoring some of the complex hormonal interplays and their effects on our body weight. In fact, weight gain is a lot more about hormones than about caloric intake! This explains why most overweight people will tell you they eat like birds and still cannot lose weight or why many women suddenly put on weight after menopause.
We tend to think that the fat we eat is the same fat that ends up in our love handles. However, the body is a complex array of biochemical reactions and the relationship between dietary fat and fat stored in our hips & buttocks is not as straightforward as it seems. In fact, eating low-fat products is not the magic key to losing weight – as many have experienced first hand. Why is this? The answer is simple but may come as a surprise: most body fat is actually made from the sugar we eat! The process works as follows: when we eat sugar – and by sugar we mean anything sweet, fruits included, but also white starches such as white rice or white bread – our blood sugar levels go up (you may have already observed this in diabetics who perform finger-pricking at mealtimes). Since blood sugar levels that are too high or too low can cause internal damage, the body is well-equipped to keep the levels in check. When blood sugar levels rise after a meal, we produce the hormone insulin. It causes the body to perform three sequential actions:
1. Insulin tells our muscle cells to take sugar up from our bloodstream. This directly lowers blood sugar levels and gives muscle cells fuel to keep on functioning. This is why exercising helps “burn off” some of the foods we’ve eaten – and by putting on more muscle mass through exercise, extra muscle can take up more sugar at a time.
2. Insulin tells the liver to take up some sugar from the bloodstream and convert it into a starch reserve for later use. This will be useful so that if we have skipped breakfast, we don’t collapse – the liver will simply change some of this starch into sugar to feed our brain & muscles.
3. Finally, insulin instructs our liver to convert any extra sugar left in the bloodstream into fat and cholesterol. These two are then shipped off to specialized fat cells in our bellies, hips/buttocks and other areas. And that’s it: the chocolate cake or the pizza you ate for lunch becomes body fat!
So, eating sweet foods or starches (particularly refined starches) makes us fat.
One of the sad consequences of many popular diets – whether low-fat or low-calorie – is that people end of consuming foods that are not nourishing on a chronic basis. Too much low-fat yoghurt, too many low-calorie snacks…and often too few unrefined, truly nourishing foods such as vegetables, legumes and unprocessed animal products. Over time, the body can simply no longer compensate for this chronic & insidious malnutrition. Our metabolism then slows down due to nutrient depletion, as there is less and less high quality fuel to burn. One of the main organs responsible for metabolic rate is the thyroid, which slows down accordingly. As a result, low-fat and low-calorie diets may be partially responsible for the modern-day hypothyroidism epidemic observed especially amongst women. Many individuals with hypothyroidism are overweight and tend to restrict fats and calories in their diet. And thus beings a vicious cycle: thicker waistline = reaction: fewer calories, slower metabolism = thicker waistline etc …This cycle can only be broken once individuals accept to go back on a higher calorie but more nourishing diet.
Chronic stress is another significant obstacle to weight loss. When we are chronically under pressure (like a never-ending to-do list, a job we don’t enjoy, or a long-standing family issue) our body produces cortisol. This hormone allows us to “keep going” when we are quite exhausted. But the price is high! Indeed, all of our hormonal mechanisms evolved millions of years ago, when “stress” meant running away from a predator. For this reason, cortisol ensures that our muscles & cardiovascular system have enough steam to literally escape the tiger or mammoth. This means that cortisol raises both blood sugar levels (so that our muscles have fuel to burn readily available) and blood pressure (so that our muscles & heart have enough oxygen to keep going). The trouble is that we experience modern-day stress while sitting motionless behind an office desk or in the car. Our muscles don’t burn off the extra sugar put into circulation and our heart really doesn’t need to beat any faster. Over time, this leads to chronically high blood sugar levels and therefore elevated insulin, resulting in constant fat storage and very little burning of fat. The lesson learned comes as no surprise: take it easy, relax, and you will shed those pounds faster!
Next time you hear about the latest low-calorie diet or reach for the low-fat mayonnaise– remember: weight gain is not about the number of calories but about food choices, stress management and their effect on our internal hormonal mechanisms.
Fact: Genetics have a role to play in how heavy we are.
Studies on identical twins have shown that our genetics definitely determine where we put on weight (abdomen? hips? thighs?) and how we react to various nutrients like fats, carbohydrates and proteins. That being said, all of us have the power to manipulate our biochemistry to some extent – by using easy intervention like dietary or lifestyle changes – and thus achieve a figure that we can be happy with!