How to choose a diet that suits you and where each type of dieter tends to slip

Some people lose weight with intermittent fasting, while others on the same plan start binge eating or get low blood sugar. Calorie counting is the same: for some it is the answer, for others it leaves nothing but stress and obsession. That is why the book I co-wrote, Eat to Succeed (a Korean-language book, 2026), says there is no perfect diet that suits everyone.

One study put four well-known diets head to head. It took 160 adults who were overweight or obese and had high blood pressure, abnormal blood lipids or high fasting blood sugar, and assigned 40 each to a carbohydrate-restricted, a fat-restricted, a calorie-restricted and a macronutrient-balanced diet for a year. After a year, average weight loss was between 2.1 and 3.3 kg on all four, and between half and 65% of each group stayed to the end. How much weight people lost had almost nothing to do with which diet they were on and was clearly tied to how closely they said they had followed it.

A pooled analysis of 48 randomised trials of named diets (7,286 people) found the same: weight came down whether people cut carbohydrates or fat, and the differences between diets were small. The authors wrote that the results support recommending whichever diet a patient will stick to.

So before asking which diet works faster, it helps to know what kind of person will be keeping it up for the next three months.

Given the same calorie app, some people say seeing the numbers keeps them going, and others say logging every bite feels like homework. The book sorts dieters into three broad types. Few people fit one type exactly and most have traits of several, but knowing your main tendency lets you build a plan that suits you.

Planners who prepare meals in advance and write down their weight and exercise without fail keep going thanks to those records. But when one day goes off plan they tend to feel everything is ruined, and chasing numbers can become stressful. The book quotes what we say to people like this word for word.

"The goal is progress, not perfection. If you follow the plan 80% of the time, that is success."

Over three months, sticking to it on 70 of 90 days is plenty. The same goes for the scale. Your body can keep changing in a week when your weight does not move, which is why the book says there is no need to fixate on a single number. If your records have stopped helping you and started acting like a scorecard that pushes you around, it is time to record less.

Some people find logging every meal so tiresome that they give up within days. For them, as the book puts it, calorie counting tends to leave only stress and obsession. The book suggests the 3.6.9 diet for this type: rather than forcing yourself to hold out when hungry, you fill up on clean, filling food.

• Keep one rulewithin "plenty of vegetables, some protein, less carbohydrate and processed food", try as many foods and dishes as you like.
• Pay attention to taste, smell and texturemindful eating keeps the pleasure in meals.
• Weigh yourself once a weekonly to check which way things are heading.

That said, if you already eat three regular meals and do not binge, there is no need to split your day into five eating times as 3.6.9 does. What this type needs to watch is confusing eating for emotional reasons with eating because the body needs food. As the book says, real hunger does not strike suddenly; it builds gradually. If a craving for a particular food such as chocolate or fried chicken hits less than an hour after a meal, the signal may be coming from your head rather than your stomach.

Some people put off exercise on their own but never miss it once they have arranged it with someone. For this type the book suggests starting with friends or family, joining group fitness, yoga classes or a running club, and setting up healthy cooking get-togethers. Posting your progress on social media or joining an app challenge helps too.

Doing it together gives you energy, and it can also knock you off course. You start measuring your pace against someone else's, it is easy to drop your own rules at work dinners and gatherings, and when the person you started with quits, you are likely to stop too. As the book says, the person to compare yourself with is yesterday's you, not someone else, and it matters that you keep going even if your family or friends give up.

Once you know your type, it helps to put it on one page. The book describes writing a personal diet statement, sticking it somewhere you look often such as the fridge door, and reading it whenever you waver. The statement has four parts.

• What kind of dieter am Ie.g. I am a social dieter. It is hard on my own but I can do it with others.
• My strengthe.g. I keep my promises.
• My weaknesse.g. my willpower is weak when I am alone.
• The approach that suits mee.g. find an exercise partner, sign up for a group class and share progress with friends.

Once you have chosen an approach, what comes next is time. The book repeats what we always tell patients in the clinic: "Any method is fine, but keep it up for at least three months. Once it becomes a habit, nothing is more powerful." Eating a big meal along the way does not mean starting over. Just go back to your usual pattern at the next meal.