“This book didn’t teach me to ‘not eat’—it taught me ‘in what proportions to eat.’ For me, it’s more than just a weight-loss guide. It shows me how to easily adjust my daily meals, reduce the burden of cooking, and enjoy eating vegetables deliciously.”
—Reader review (Amazon.co.jp)

“The bento-box diet doesn’t require counting calories—just filling the box according to specific proportions. I started making bento using these ratios right away. Cooking has become fun, and I even bought a new bentwood bento box (laughs).”
—Reader review (Amazon.co.jp)

★ Before its release, it already ranked No. 1 in its category on Amazon. Author Yoshimi Saito spent 30 years repeatedly dieting and regaining weight; despite being overweight, she was diagnosed with “malnutrition.” Drawing on this experience, she devised the 3:2:1 Bento Box Diet and successfully lost 15 kilograms herself.
★ The method is extremely simple: In a bento box, arrange side dishes and staple foods according to a ratio of 3 parts dietary fiber, 2 parts carbohydrates, and 1 part protein. There’s no need to count calories, weigh food, or engage in strenuous exercise. The physical capacity of the bento box naturally controls portion sizes, making it more intuitive than crunching numbers. The book includes 116 recipes.
★ The supervising physician, Takafumi Kudo, is a specialist in diabetes. After graduating from Fukuoka University’s Faculty of Medicine, he studied in Ireland and Australia, and now practices at the Kida Internal Medicine Diabetes & Thyroid Clinic in Shibuya, Tokyo, where he treats lifestyle-related diseases and diabetes. He is the author of books such as “How to Eat to Reduce Visceral Fat.”
★ “Too fat yet malnourished”—this statement is not a contradiction. If you simply cut your meal size in half, along with the calories, you’re also cutting proteins, vitamins, and minerals in half. Your body will interpret this as “famine” and switch into energy-saving mode, lowering your metabolism and making it even harder to lose weight. This is why the author proposes the 3:2:1 ratio.
★ The author has personally guided over 50,000 meals and mentored more than 1,000 people, with about 90% of her students reporting changes in their figure, constitution, and weight. She is an ambassador for Nikkei Cross Woman. This book is for those who don’t want to starve, don’t want to count calories, and just want to enjoy eating well.

“I can’t stick to dietary restrictions or exercise…
I’m not good at counting calories…
I want to lose weight in a healthy way…”
For those with these concerns, Saito Yoshimi, an expert in “eating-your-way-to-weight-loss,” introduces the “3:2:1 Bento Box Diet.”
Simply fill your bento box with side dishes and staple foods in the ratio of 3 parts fiber, 2 parts carbohydrates, and 1 part protein. With this magical ratio, your nutrition becomes naturally balanced, and your body gradually transforms into a healthy, slimming physique. There’s absolutely no need for strict dietary restrictions or intense workouts—and you don’t have to bother with calorie counting or complicated nutritional knowledge.
This book features over 100 easy-to-make side-dish recipes, categorized by nutrient. On busy days, you can even use pre-cooked or frozen foods. You don’t have to push yourself too hard—this approach is perfect for those who prefer to take it easy. With just this one book, start enjoying delicious meals and losing weight naturally every day!

Yoshimi Saito
Representative Director of Eat Balance Co., Ltd. and Chairperson of the Vibalanche Diet Association. After repeatedly dieting and regaining weight over 30 years, she was diagnosed with “malnutrition” despite being overweight. Drawing on this experience, she developed a weight-loss method that does not rely on dietary restrictions and emphasizes nutritional balance, successfully shedding a total of 15 kilograms herself. Guided by the principle of “losing weight while eating,” she founded the “Vibalanche Diet” and has since coached more than 50,000 meals. She promotes a dietary approach that uses bento boxes to achieve nutritional balance, helping people build healthy, slim physiques. She is the author of “Lose Weight Healthily Without Worrying About Calories: The Convenience Store Three-Item Diet.”

Chapter 1: The Steps of the Bento Box Diet
Chapter 2: Recipes Using High-Fiber Ingredients
Chapter 3: Recipes Using Carbohydrate-Rich Ingredients
Chapter 4: Recipes Using Protein-Rich Ingredients
Chapter 5: Soup Recipes