The health and weight-loss benefits of skipping breakfast

If you want to be lean and burn fat, have a lie-in.

‘Breakfast is the most important meal of the day’ was an advertising slogan created in 1944 by General Foods, makers of the breakfast cereal Grape Nuts, based on no evidence whatsoever.

Still, it was catchy and memorable, so it got picked up by nutrition experts who decided to run with it and are still out there running with it down through the decades.

As a nutritionist, I hear people regularly say that they have no appetite first thing in the morning. Yet they feel they ‘should’ eat something anyway.

Oh, the irony. So many people overeat and snack constantly, yet at the one time of day when they have no appetite the power of cultural conditioning kicks in and they force themselves to eat something anyway.

You’ve probably heard it said often enough: breakfast means, literally, breaking the fast — you haven’t eaten since the evening before, so you must be fading and in need of something to see you through to lunchtime.

This dietary dictum is based on our knowledge of blood sugar. This sugar — glucose — provides you with fuel. It comes from the carbohydrates you eat, though it is also readily available from protein and fat.

That’s the theory, but in practice, as you may have noticed, once we are up and about and sufficiently roused from sleep, most of us feel fine and do not collapse into a feeble heap if we don’t eat anything. We start our day and go about our routine, despite not having eaten for many hours.

Having said that, some people have metabolic issues that require them to eat soon after waking — for example, those with diabetes or metabolic syndrome, a condition linked to obesity and heart disease and characterized by chronically high levels of insulin. These people are more likely to suffer from low energy in the morning and need to eat soon after waking.

The role of the circadian rhythm

There is a reason why most people have little or no appetite on waking: the human body clock (aka circadian rhythm) and the production of cortisol. Cortisol is an adrenal hormone produced cyclically: levels start to rise between 3 am and 6 am, and within thirty to forty minutes after waking, most people experience a two- to three-fold surge in circulating levels. In what is termed the ‘awakening cortisol response,’ cortisol mobilizes glucose and promotes gluconeogenesis, the manufacture of glucose from fat and protein.

As the morning progresses, cortisol levels start to decrease; in the healthy individual they are at their lowest by night-time.

While you were sleeping

The circadian rhythm orchestrates hormonal balance, with most of the action taking place at night while you are in sleep mode. To sail through the morning with good energy levels, you need adequate sleep.

Sleep is mysterious, and so too is nocturnal metabolism. Your biological clock responds to the sun's rising and setting so that our patterns of sleep and wakefulness match the rotation of the Earth about its axis. It was Charles Darwin who, after visiting the Galapagos Islands in 1835, first realized that life is cyclical, and he later published a treatise on the daily pattern of leaf movements in plants. It is well known now that this invisible clock ticks in most animals too.

Growth hormone

Insulin is the dominant hormone during and after meals, lowering blood sugar and sending any excess to storage in your adipose tissue (body fat). But at night, as you sleep and fast, another hormone dominates metabolism: growth hormone.

Growth hormone is largely why sleep is so important for metabolism and weight control. It helps maintain energy homeostasis by regulating glucose and stimulating the release of fatty acids from your adipose tissue and the production of ketones. Fat and ketones provide your brain and the rest of your body with the fuel required to perform numerous metabolic functions.

That is why intermittent fasting is so effective for weight loss. If you want to lose weight, it’s fat, not glucose, that you need to burn. When you fast and sleep, you make the switch from glucose to fat.

The secretion of growth hormone starts at the beginning of the first deep sleep cycle and is then secreted intermittently during sleep. However, peak growth hormone secretion is inhibited if the onset of sleep is delayed.

“GH deficiency is associated with increased fat mass, particularly deposition of visceral fat, which is known to be a prominent risk factor for the development of cardiovascular morbidity and mortality.”

Lack of growth hormone during fasting also has a negative effect on muscle. As you fast, growth hormone stimulates the release of free fatty acids and preserves lean body mass. Lack of growth hormone during fasting increases protein loss by approximately 50%, accompanied by a similar increase in muscle protein breakdown. Thus, just by sleeping well, you burn fat and build lean mass.

So why cut short all that fabulous night work by having something to eat when you get up? If you are not hungry, it’s because you still have fuel in your blood. Therefore, anything you eat will be surplus to requirements and end up in your adipose tissue.

Although there is no official definition of intermittent fasting, the fundamentals involve a pattern of eating based on extended periods of abstinence. The overnight fast involves ‘time-restricted feeding,’ where food is limited to a window of around 7 hours. Having your first meal at midday and eating nothing after 7 pm works well for most people.

Delaying the first meal of the day or just powering through to lunch is the easiest form of intermittent fasting. After all, you’re asleep for half the time, busy burning fat and building muscle.

For more details of the most effective way to lose weight permanently, see this article:

Why “Eat Less, Move More” Doesn’t Work for Weight Loss

image