Nutrition makes a huge difference to your work performance. This may sound like your mother, but you can get better results from eating a better diet. And the most important meal of the day is breakfast.
If you plan to operate at peak levels for ten or more hours, a good breakfast is vital. There’s been a lot of research on the subject over the past 50 years or so. Some of the most relevant research to modern Knowledge Workers was carried out during – and immediately after – the Second World War.
Writing in her 1954 book “Let’s Eat Right to Keep Fit”, American nutritionist Adelle Davis says:
“You determine how you will feel throughout each day by the type of breakfast you eat. You can produce inefficiency in yourself by eating too little food or too much of the wrong kind of food. Your breakfast establishes how readily your body can produce energy that day, or, more specifically the amount of sugar in your blood. Your energy production, which corresponds to the amount of sugar available, determines how you think, act and feel. Energy is produced in your body by burning (oxidising) sugar alone or sugar and fat together.”
Importantly, Davis points out that your nerve and brain cells can only produce energy from sugar. So, basically if you’re going to think on you feet and get things done you need an adequate flow of energy, which means eating enough food to supply your sugar needs.
In pure technical terms, your normal blood sugar after 12 hours of not eating (i.e. first thing in the morning after waking) should be around 800 to 1200 milligrams per litre of blood. If your blood sugar drops below 700 milligrams per litre of blood you’ll feel fatigue. At levels below 650 milligrams you’ll feel exhaustion and can expect headaches, weakness and even wobbly legs. You may even feel nausea. Go lower again and you’re in danger of fainting.
Davis quotes some research, which fed people different types of breakfast and looked at their blood sugar levels:
Black coffee only: blood sugar drops quickly, irritability, nervousness, hunger fatigue and exhaustion sets in after one hour and gets worse as the morning progresses.
Two doughnuts and white coffee with sugar: an initial rapid rise in blood sugar but within an hour levels fall with resulting inefficiency and fatigue.
A ‘basic breakfast’ of glass of orange juice, two rashers of bacon, toast, jam and white coffee with sugar: again a rapid rise, but levels falling below normal within an hour.
The same ‘basic breakfast’ but with porridge served with sugar and milk: the same rapid rise, but levels dropped faster than before and to lower (i.e. low efficiency) levels.
‘Basic breakfast’ plus a glass of whole milk with 2 ½ tablespoons of skimmed milk powder: blood sugar rises and stays a high levels throughout the morning.
Basic breakfast’ plus two eggs: Same high-efficiency levels.
The researchers also tested the same people after giving them a simple lunch. Interestingly, the people who ate the better breakfast experienced more efficient blood sugar levels throughout the afternoon, while those with the less efficient breakfasts found blood sugar levels again dropped away quickly.