Most traditional, subscription-based journals publish articles free on a "closed-access" basis, with the option for "open access" for authors who can afford it. By closed access, I mean the traditional mode of access in which those who want to use an article pay to obtain it, either directly or through subscriptions.
There are a number of ways you can go about getting your article FREELY published without article processing/ publication charges (so-called APCs). You can prepare your article first, generically, and then seek out a traditional, subscription-based journal you want to send it to and then revise and format it in line with their instructions/ guidelines for authors. You may also seek out a traditional, subscription-based journal of your choice and then prepare your article, ab initio, according to their instructions/ guidelines for authors. Both have pros and cons, and researchers have their preferences, which, in fact, are fluid, and do change from time to time.
There are websites/ services now you can use to search for traditional, subscription-based journals that may be relevant for your article. For example, Journal/ Author Name Estimator (JANE). Website: http://jane.biosemantics.org/
Elsevier also has such a service, the Journal Finder.
Website: https://journalfinder.elsevier.com/#
Whether you go for discipline-specific journals or interdisciplinary journals is a decision to make based on the internal academic/ scholarly/ research preferences and policies in your department, faculty or institution and, of course, your own preferences. An example of a discipline-specific journal in health promotion is American Journal of Health Promotion. Other than going for discipline-specific journals, there are countless high-quality journals where you can publish an article related to health promotion, workplace issues, occupational health issues. For example, many public health journals will be suitable.
Good news is there are currently a number of open access journals that also publish articles without charges because such journals are sponsored/ funded by governments or regional bodies, and they are also of high quality.
Due to obesity, occupational health and health promotion is under public health, then I am suggesting you to publish your article in public health journal such as
Malaysian Journal of Public Health Medicine (MJPHM), International Journal of Public Health Research (IJPHR) or Borneo Journal of Medical Sciences (BJMS).