“Athletes tend to focus on their spectacular performances,” states Professor Ishihara, “but in reality it’s the grueling daily practice regime that supports them. If you can’t practice because of ongoing injury, you can’t continue your athletic career.” Similarly, Professor Ishihara says that top businesspeople with an always-on mentality must be able to pace themselves to complete tasks with a high level of concentration and to balance work, hobbies, and family for a lifetime of good health. The top ultra-marathoners that the Professor meets in his research also excel in their ability to adjust their entire lives to the race, not only in terms of their race-day behavior but also with the help of those around them on a regular basis. “When we studied the eating habits of ultra-distance runners, those who run over 100 km, we were surprised to find that top-tier athletes have a detailed plan of where and what to eat. The more real the image of the final output of this regime becomes in the athlete’s mind, the more specific are the things that need to be done to get there, and the sooner success comes as a result. This, I think, is a point in common between businesspeople and ultra-distance sports.”

The first recommendation for businesspeople interested in nutrition is to manage their blood glucose levels. This is a suitable regime regarded as a quick PDCA because food input and exercise can be evaluated directly in terms of outputs such as blood glucose levels. It’s desirable to control blood glucose levels since concentration and efficiency are affected detrimentally if they are too high or too low. However, the degree to which blood glucose levels rise after consuming the same amount of food varies according to body type. Professor Ishihara’s area of expertise relates to blood glucose control in people involved in endurance sports such as running. The Professor used himself as a test subject to confirm that sudden rises and falls in blood glucose levels reduce performance and to determine the right amount and timing of intake. He used a blood glucose meter with a sensor attached to the arm for measurement. Similar measurement tools are also available commercially, so it’s recommended to try them casually. Performance in sport is not necessarily identical to performance in business but large fluctuations in blood sugar levels should be avoided in terms of long-term health. The question is, what kind of intake can prevent spikes in blood glucose levels? Professor Ishihara offers some specific advice. “Reduce the amount of carbohydrates you eat at lunchtime and consume dietary fiber such as vegetables first. As the saying goes, ‘it makes your stomach upset.’ Fats and oils stay in the stomach longer, so blood glucose levels are less likely to rise. Eating slowly also helps.”

When thinking about ‘how we eat,’ nutritional balance cannot be ignored. It is widely recognized that a balanced diet is the basis of good nutrition but what is less well recognized is that the optimum balance differs from person to person. “Do I want to gain muscle, improve my stamina, or lose weight? Different goals and body states require different PFC (protein, fat, and carbohydrate) balances.” Professor Ishihara recommends imitating the eating habits of people who have achieved their target body shape and performance to find out more. “Try recording your diet and weighing yourself every morning for about two weeks, assess the changes in your weight and body fat percentage and evaluate whether you’re getting closer to your goals. If not, repeat the process of modifying them. First, set specific performance goals, then examine your body and repeatedly run PDCA through weighing your body every morning. This way, you can determine your own unique nutritional balance without being confused by vague general health and nutrition information.”

As you grow older, your optimum nutritional intake changes. We asked Professor Ishihara how young, middle-aged, and elderly people should eat and move in order to perform well. “You need to change what you eat in stages depending on your life stage. Middle-aged and older people need to eat in a way that reduces fat and takes into account the prevention of metabolic obesity and lifestyle-related diseases since their ability to process nutrients is reduced compared to when they were younger. Furthermore, as they get older, they should eat more protein in terms of PFC balance. On the other hand, their energy intake does not need to be reduced too much. When entering old age, people lose muscle mass and weight and their appetite decreases. If you feel that you’re eating less, or that you’re losing weight even though you eat the same amount, you should actively eat meat, fish, and even rice.”

Professor Ishihara says that business performance is built not only by eating but also by a combination of movement and rest. “Food is important because a healthy body and brain are made from the food we eat which enables us to continuously work. Nonetheless, having a regular exercise routine will help keep your bones, muscles, and blood vessels healthy. Also, exercise has the effect of promoting the growth of new neurons in the brain along with improving the environment of the intestines. It’s important to sleep and wake up early, move, and eat properly.” In considering how to move, Professor Ishihara recommends referring to the Ministry of Health, Labour and Welfare's Physical Activity and Exercise Guide for Health Promotion. It provides specific guidelines for health promotion and whole-body exercise is the basis of it, but the 2023 edition contains recommendations for regular muscle training and avoiding too much sitting for adults and the elderly. Professor Ishihara adds: “If you’re in a workplace where people spend a lot of time at their desks throughout the day, there are measures you can adopt as an organization, such as introducing standing desks or encouraging people to commute by bicycle/running.” Nevertheless, the problem for many businesspeople is that they are so busy at work that they have no time for exercise. Professor Ishihara points out that statistics clearly show that the main cause of this problem is long working hours. “Aren’t work-sharing and creating a working environment where women can continue to work longer also important to ensure that society remains healthy? ‘Japanese longevity and good health’ is a brand. I hope that companies and society will be more open to health promotion.”