Regarding nutrition, my fiancée and I went through a very interesting 12 week "gut cleanse" from mid-October to December.
A friend of mine is a nutritionist and she asked us to be the guinea pigs for a cleansing program she's working on.
TL;DR : Gut health has a major impact on your ability to lose fatty weight and digest foods optimally. The program worked wonders for us, as we both lost 5kgs within 4 weeks, and we didn't train more than 3 times a week. (I normally swim 3 times a week, but there were some weeks where I only swam once due to work)
I would definitely recommend it to anyone who struggles with bloating, indigestion, heartburn, flatulence, stomach pain, etc., or anyone looking to just get a healthy gut.
The main goal of the cleanse was to see which foods "triggered" our gut - in other words, which foods were detrimental to our digestion.
I had a massive farting problem since I was small (nickname in primary school was Winde in Afrikaans because I could fart when I wanted) and my fiancée had regular heartburn/sooibrand.
I also had a bloated stomach on a daily occasion due to my love for bread and milk.
To cut a looooong story short, I don't fart nearly as often as I used to (now a fart is actually funny again and not a burden), stomach is rarely bloated and the only times I feel bloated is when I finish a session in the pool (chlorine is a major bloating ingredient), eat anything made from wheat/corn other than sourdough, or when I drink/eat dairy.
I didn't train too often (swam twice a week, sometimes 3 or 4 sessions), and weight loss wasn't the goal, but we both managed to cut 5kgs in under 4 weeks. (I'm 179cm and weighed 83kgs before we started - body is a swimmer-type, so weight attributable to fat is instantly noticeable)
The nutritionist mentioned after we reported the weight loss that many people struggle with losing weight due to an unhealthy gut and foods that prohibit their gut from really functioning as it should.
I believe her 100% - I lost 5kgs without too much training and I ate much more than usual, albeit a lot cleaner (e.g. just salt and pepper on steak instead of mushroom sauce)
So we have incorporated this way of eating and preparing food into our daily lifestyle and I can honestly say it is worth it.
I didn't post too much detail on the diet due to it being her source of income, but if you are interested, I'll refer you to her.
(DISCLAIMER: I don't get anything from this - she doesn't know I'm posting this, but many of our family have also gotten into contact with her due to seeing the results)