The title of this just totally enraged me. And I'm still angry that you as the "friend" are writing this, you as the "friend" are discussing your friend's wife, and that it's about a woman's health, fundamentally. This lady is young enough to be considering another child, and has been told she has serious health risks. The way her eating is described shows she is understandably eating common foods and her weight is increasing, fitness decreasing. Being out of breath to require an inhaler, approaching 300 pounds, and having joint problems with two young children is not pleasant for her.

And her husband is no longer sexually attracted to her.

I'm enraged that you as a male are writing this from the husband's perspective, and that the wife's experience is literally being exploited for Medium claps -

So #1 - she needs to cut out the refined carbs (bread, pasta, sweets, breakfast cereals)

#2 - she should invest in a fitness tracker that works for her

Here I describe making the lifestyle changes to become fit and healthy. I have recently cut out all added sugars of any type - this includes candy and dessert which I "could" eat because I am very active.

https://asterling.medium.com/c1c23e23ccfb

The single biggest thing your "friend" can do to help his wife is to himself, cut way back on carbs and prepared foods and to help her to understand these foods are what is destroying her health. There's a big health controversy raging right now about the Carbohydrate-Insulin Metabolism (CIM) theory of weight gain and the old-fashioned "calories in-calories out" theory. I know from personal experience that what we eat is extremely important. Refined carbs and prepared foods encourage overeating for a variety of reasons. Someone who "goes on diets" without making huge lifestyle changes (i.e. what I suggested - dump ALL of this type of food, eat only basic proteins, fruits, and vegetables) will lose weight but the more weight a person loses, then returns to prior eating habits, the more quickly they will gain it back and the more damage it does to their normal metabolism.

This s**t just ENRAGES ME but every woman who believes they want to be healthier and fitter needs to know this about the deadly refined carbs, whether they are sugar, high-fructose corn syrup, or bread/cake/pasta products.

After only a couple of days refined carb-free she should feel more energetic and the inflammation that is causing her joint pain and continued weight gain will begin to recede.

You're welcome. I'm now earning in the top 5% of females in US, and am in top 5% of fitness for my age and gender as well. No thanks to @Medium though I hope I've helped a few people here.