Hello there and thank you for your question!
In theory, weight loss may occur if you consume less calories than your body uses (through daily living and physical activity). However, there are other factors that can contribute to your weight such as your age, sex, metabolism and environment.1 I encourage you and your wife to consult with a dietitian who can fully assess both your nutritional needs and work more closely with you two to help achieve your desired weight loss goals.
In my opinion, the best meal plan is one you can stick to. We have several meal plans you can try, such as the 3 Slow Cooker Main Dishes and 5 Vegetarian Dinners. You can always customize the recipes to fit your needs and personal preferences!
There are many ways to improve your health regardless of weight loss, such as improving your eating habits and becoming more physically active. I encourage you and your wife to explore our Lifestyle pages on how to build more positive habits for long-term health and wellness. Check out these pages: Eating enough fruits and vegetables helps fight disease and boosts energy and Healthy fats are really important for your brain and your body.
Hope this helps!
1. Institute of Medicine (US) Subcommittee on Military Weight Management. Weight Management: State of the Science and Opportunities for Military Programs. Washington (DC): National Academies Press (US); 2004. 3, Factors That Influence Body Weight. Available from: https://www.ncbi.nlm.nih.gov/books/NBK221834/