What I find the most appealing about your Q is the idea of you and your wife working together as a team with a common goal. That's great!
Hi weightbanger, I'm a complete noob... but maybe I can make a few suggestions that may help you and your wife out. You've said a couple of things that made my ears ring so i'll address those first.
First, your BMR shouldn't be ignored or modified. It is what it is. The term "Basal" means "Base" - i.e. the lowest point. There is no point to knowing your BMR if you are going to ignore it. BMR is the number of calories your body requires while in a coma. Many have read this statement hundreds of times, they know it by heart. But too often they misunderstand the word "requires". It means - It's not negotiable. So, your BMR is your starting point and you move up from here - not down. The consequences of going below your BMR for a sustained period will slow and sometimes contradict all of your efforts long term. It's a classic dieting mistake. Moving on...
You both need real goals. I'll tell you what I tell my own clients -- take that annoying bathroom scale and throw it in the closet and leave it there. At least for a while. Few months. Weight loss is NOT a good goal. It has too many misinterpretations and negatives both physically and mentally. It does more too frustrate then it does to motivate. Also, weight is a measurement of gravity - and gravity is still invisible. You don't see "weight" looking in the mirror or when trying on clothing. What you see is size. And SIZE should be your goals. Size is meaningful. It's reliably measurable, Its what you see in the mirror, and it determines how clothing fits. When others see you - they see size... not weight. So start by setting reasonable goals about size reductions. If your size 38 jeans now, and want to be in size 32 - great, but baby steps... mid-goals of 36 first, then 34, then 32. This promotes motivation and it makes a difference in achieving long-term objectives. If that 'size goal' means the loss of 5 lbs of body fat OR 50 lbs, the goal remains the same regardless of how much body fat was reduced.
Ok... about meals. You hopefully know that adipose tissue is created when blood sugar rises above your tolerance levels, releasing insulin, and storing as body fat. If not, you do now.
So... the trick to not adding to body fat is normalizing blood sugar. This is EASY to do and it doesn't take any special diets or meal plans. It only takes an good understanding of the digestive process.
Too many concentrate on the affects of foods AFTER they digest or the volume of calories. And this is fine, but the rate in which foods digest is equally important too. Foods that digest quickly (simple carbs and non-fibrous starches) digest rapidly - flooding in calories. This causes blood sugar to rise..which of course releases insulin.. and you know what that does. Foods that digest slowly "spoon feed" calories and nutrients into our system. This doesn't spike blood sugar but rather it raises our metabolic rate, and keeps it there for a longer duration.
I honestly don't care what food products you consume - as long as they are less processed, low sugar, and slow digesting foods, and that your eating a meal (not a snack..a meal!) ever 3 or so hours. If you do you won't be adding to body fat. If you remain AT or just slightly ABOVE your BMR - the energy for movement and activities will come from adipose tissue. You'll feel great, be happy, strong, and remain active. If your wife ins't into the gym..that's OK..honest. Go for a walk, or try cycling with her something. Think "Happy wife = happy life!"
So remember: SLOW digesting foods. Let the calories "trickle" in and you'll do great.
Nutrient balanced: 40:40:20 diets, or 40:30:30 diets have proven themselves time and time again. Nutrients feed the body. Calories are ONLY for energy. Something to keep in mind, If your hungry often, it means your body is starving for nutrients more then calories.
- Simple carbs / non-fiberous starches digest in a few minutes to an hour or so. Limit these to less then 10% of your total carb percentage.
- Complex carbs - 1-3 hours. Its exceptionally difficult to over-consume raw veggies. Esp dark green veggies. Eat ALL you like.
- Proteins 2-5 hours avg. (please avoid soy... it can cause thyroid reactions for some ppl)
- Fats 4-12 hours avg.
Note on fats: Don't do "low fat" processed foods! Low fat processed foods almost always mean high carb. As you can see above - fat's don't always make you fat. They digest too slowly too add to adipose tissue. And of them, only long-chain fats will. The short and medium chain fats don't unless your biting off chunks of fat from a slab of prime rib. If you limit your intake of ALL fats to less then 30% of your total calories, there is no need for low fat foods. So enjoy! Fats rich in Omega3 and 6 are great! Again... no limit of these type foods... Eat up and ignore the calories on these foods because they wont add to fat. Saturated fats take DOUBLE the energy to digest - again, within reasonable limits - saturated fats help maintain a high metabolic rate. Don't be scared of them - use them to your advantage.
And... that's about it.
Sorry so long and preachy... My passion is health and fitness.. so I hope it helps..at least a little.
Let me know how things work out.