Eat less and exercise more. That’s the simple solution conventional nutrition wisdom says helps us fit into our skinny jeans. Yet studies show that in the long term, dieting is ineffective. Why’s that?
Diets fail for many reasons. People may not follow their eating plan properly, make healthy choices or control portion sizes. The opposite may be true for others, as they become overwhelmed or obsessive and develop an eating disorder or lasting negative relationship with food. When people restrict kilojoules, they often limit food groups too. “Fad diets – the sort often accompanied by ‘magic’ pills, injections or potions – often require you to do that, which may cause hunger or overeating and related nutritional deficiencies,” says registered dietician Yolandé van der Riet.
“Low-quality foods are often more easily accessible than their healthy counterparts. People might have a short-term goal, such as fitting into a wedding dress, but once the milestone passes lose their dietary direction. Or their weight might reach a plateau, and instead of persevering, they lose motivation. Others might enjoy the initial success of their hard work, only to over-reward themselves with treats or get complacent.” There must be a better way to lose weight – for good. Here, Yolandé answers your kilojoule-counting FAQs. Hint: the answer isn’t black and white.
How many kilojoules does the body need?
Various formulas exist to calculate energy needs, but on average, an adult woman consumes 7 950kJ to 9 620kJ per day. Due to our generally sedentary lifestyles nowadays, this may be too high for women who aren’t active enough.
What effect does consuming too few kilojoules have on the body?
Signs and symptoms you’re restricting your energy intake too much include chronic tiredness and lethargy, frequent infections due to a weakened immune system, hair loss and skin problems. Many people don’t know that infertility, osteoporosis, bone fractures, anaemia and early developmental problems are also linked to undereating. Even bodily functions such as breathing and thinking may be compromised due to restricted caloric intake. Decreased physical performance, frequently feeling cold, unregulated blood sugar levels, poor sleeping habits, reduced circulation and regular constipation could also indicate you’re underconsuming kilojoules. A dietician can calculate safe caloric restrictions for weight loss, and alternative ways to lower your intake include reducing portion sizes, making healthier food choices and increasing physical activity.
Can restricting kilojoules cause psychological damage?
An additional side effect of starvation or low caloric intake is depression, often, amongst other reasons, due to a lack of omega-3 fatty acids and vitamin D. The brain serves as one of the first organs to react to undereating by ‘switching off’ complex functions, such as intellect and reasoning, and focussing on survival. This, in turn, may cause anxiety, stress, obsessive and compulsive behaviour, lack of empathy, withdrawal, low self-esteem, preoccupation with food, avoiding eating in public, fear of being fat, repeatedly weighing yourself and extreme exercising. Even daily tasks – decision-making and prioritising – become very difficult to master. Initially, you may feel powerful due to resisting hunger pangs, but, eventually, an internal battle may develop between the body’s craving to be fed vs. your need to excessively limit caloric intake.
How does it affect your ability to pay attention to signals such as hunger, fullness and satisfaction?
Feeling full or satiated depends on the stomach expanding after you’ve eaten, whether you’ve consumed foods high in water, fibre, fats and proteins, and portion size. So, if you don’t consume enough energy or your portion is too small, the body won’t experience satiety and will feel hungry. Filling foods include legumes and pulses, low-fat dairy, fibre-containing foods (e.g. carbohydrates, fruits and veggies), nuts, eggs, lean meat and fish.
What matters more in terms of weight loss and long-term health, the type of food you eat or the kilojoules it contains?
By concentrating on kilojoules alone, you may consume enough energy but miss out on vital nutrients: appropriate amounts of macronutrients (proteins, carbohydrates, fats), micronutrients (vitamins, minerals, trace minerals), fibre and water. But eating excessive healthy food isn’t ideal either. There’s no such thing as healthy or unhealthy food, just healthy or unhealthy diets. The types of kilojoules and appropriate portion sizes matter equally.
Is it a good idea to cut out specific foods?
So, a healthy diet should contain the correct quantities of specific nutrients, without which the body may become deficient, which could eventually result in the reduction of certain bodily functions, diseases, and in the worst case scenario, death. That said, cutting out non-essential foods that don’t contribute to a healthy lifestyle – i.e. foods and beverages high in saturated and trans fats, salt, sugar and alcohol – isn’t a bad idea. Keep those as occasional treats only.
Do the types of food you eat affect your metabolism differently?
Yes, they do. Foods that burn more energy to be digested, metabolised (broken down) and stored increase your metabolism – protein is an example. Fats and some carbohydrates, on the other hand, your body uses less energy to metabolise – this characteristic is the thermic effect of food or TEF. Additionally, the body burns less energy to digest highly-processed foods as they have less fibre and fewer proteins.
This article was originally published on Glamour’s Sepetember 2022 Spring Issue. Grab your digital copy, here.
