Weight loss and the obsession with calories

Reviewed by Dr Mitra Dutt

We’ve been told for so long that weight loss is easy if we could just eat less and move more. Calorie counting has become the popularly accepted way to lose weight and keep weight off. But if it’s really that easy, how come many countries are facing an epidemic on obesity and related conditions such as type 2 diabetes? And, on an individual level, why do so many people struggle to lose weight even when they eat within calorie limits or, more commonly, lose weight and then put it all back on?

Calorie Counting

It is of course true that creating a calorie deficit – eating fewer calories than you burn – can lead to weight loss. When the body lacks calories, it has a better chance of burning excess body fat. However, the human body is not a laboratory machine – the balance of calories going in versus calories being burned is affected by many factors, not least of which is your metabolic rate (how fast you burn calories) and your insulin (hormonal) response to food.

The Trouble with Low-Calorie Diets

For many people, low-calorie diets bring more problems than they solve. For example:

• When the body gets the message that food is no longer plentiful, it may slow down the metabolism to preserve energy, making it more difficult to lose or maintain weight with the same amount of food. This is why some people reach a roadblock with dieting: they are eating very little but are unable to lose the excess weight.
  
• Calorie restriction usually requires good willpower. Unfortunately, willpower tends to run out eventually. The feeling of having been deprived in food choices can lead to over-eating or eating more processed or sugary treats. Cravings become stronger as your body tries to take in more food in response to the perceived scarcity – it's as if a famine is coming!
  
• A low-calorie diet can starve your body of vital nutrition. You need a good supply of nutrients to support the glands and organs involved in energy and weight management, such as the thyroid. This then negatively affects weight-loss efforts and can make you eat more to obtain the vitamins, minerals, proteins and fatty acids the brain and body need.

All Calories Are Not Created Equally

In addition to these problems with low-calorie diets, when we judge foods only by their calorie count, we are missing a lot of other information about them. A more healthy and effective way to lose weight and keep it off is to assess food on two important criteria:

1. Nutrients
2. The hormonal - insulin - response the food is likely to trigger in your body

Foods are not all created equal and neither are calories. 100 calories from cake have neither the same nutrient profile/density nor the same hormonal effect as 100 calories from avocado. The nutrients and how the body responds to the food overall have a significant role to play in weight management because these factors affect how much we eat and how incoming food energy is used and stored in the body.

Low-Calorie & Low-Fat

Low-calorie diets tend to be low-fat diets because fat contains more calories per gram than protein and carbohydrates do. The body needs fatty acids, however, to maintain the brain and nervous system, create hormones and help with the absorption of the fat-soluble vitamins A, D, E and K.

Low fat intake can lead to depletion of these important vitamins and contribute to problems with mood, immunity and energy. Natural fats found in foods help to fill us up and give us feelings of satisfaction. Importantly, they also have minimal effects on blood glucose levels, helping to reduce cravings and fat storage.

Fat & Protein

Avoiding foods higher in fat or calories can also mean you will eat less of the protein-rich foods such as meat, fish, eggs and nuts. Like fat, protein contributes to filling us up at meals and keeping blood glucose stable. Protein also has an essential role in providing the body with the raw materials for creation, maintenance and repair of important tissues such as muscle, hormones, neurotransmitters and skin.

Processed Food

Low-fat food chosen for their low calorie count often include grain-based and processed foods that are high in starch, sugar and additives and low in nutrients. The higher the sugar content of a food, the more it has the potential to cause sharp spikes and falls in our blood glucose levels. Frequent highs and lows in blood glucose can drive food cravings but, more importantly, they have been seen in studies to predispose people to metabolic disorders such as excessive weight gain, diabetes and high blood pressure.

Glucose and Insulin in Weight Management

Whenever blood glucose rises, the hormone insulin rises to take glucose and other nutrients out of the blood stream and into the cells where they are needed. This keeps blood glucose within healthy limits. If insulin levels are always high because of a sugary diet or because the body isn’t coping well, a cascade of health problems can occur.

High glucose and insulin in the body can be a significant obstacle to weight loss because:

• Glucose that is not needed can end up stored as fat in adipose tissue.
• Insulin is often called the 'storage' hormone. It prevents the body from burning body fat, so it interferes with weight loss.

Starch is not your friend

Sugary foods like sweets, cakes and biscuits are recognised by most people as obstacles to weight loss. But many people don’t realise that starchy foods such as grains and root vegetables can also be problematic. Foods such as bread, pasta, rice, potatoes and cereals are very high in starch, which is broken down into glucose (sugar!) when you eat them.

But... Unrefined Carbs?

The fibre content of unrefined foods high in carbohydrates such as wholegrains and root vegetables helps glucose from these foods to go into the bloodstream slower than from refined carbohydrates such as white-flour products (pastries, white bread, white rice etc.). Eating these foods with fat or protein can also slow down their impact on blood glucose. But, ultimately, high-carb foods deliver high amounts of sugar into your bloodstream. This is why the nutritionist regulating body – the British Association for Nutrition and Lifestyle Medicine (BANT) - suggests that grains and starchy vegetables are best restricted to no more than a quarter of the plate and that, for people wanting to lose weight, this quarter portion is reduced even further.

Personalisation

A growing number of doctors and nutritionists working in weight loss and type 2 diabetes help patients to identify and limit high-carb foods. To compensate for the lower carb intake, protein-rich foods such as meat, fish, eggs, nuts, beans and tofu are placed at the heart of the diet, with lots of leafy green and colourful vegetables. These are the vegetables that grow above ground, rather than the root vegetables that plants use for storing their sugar. People eating like this report less hunger, fewer food cravings and more balanced energy and mood. However, anyone taking prescription medications must be monitored because this kind of diet change can be powerful and interfere with medicines to a dangerous extent.

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