Hi there, thanks for asking! Please note that every person is different and your personal circumstances may require a different approach. Especially if you're underweight due to some underlying medical condition. In which case I'd strongly recommend seeking advice from your doctor.
That being said, my short answer is: yes. If you're underweight, eating more/getting more calories in should be the way to go. To gain weight, your input of calories should exceed your output of calories. In other words: you need to eat more than you burn.
Every person has a certain amount of calories and nutrients which are necessary to keep your body healthy and running. The amount of calories needed depends on various factors such as your length, weight, and activity level. For men, the average amount of calories needed a day is 2500, of which about 500-600 are taken at breakfast and 600-700 are taken at lunch, generally. By skipping breakfast or lunch, you miss out on calories, which can lead to unwanted weight loss, if you don’t catch them up during the day.
If taking Jake helps you not skip meals, Jake could be a good solution, give it a try.