Interesting programme I saw lately - you might have too.
Was about 2 identical twins (Drs) who looked at the latest 'fads' of zero sugar diets (and high fat) vs zero fat diets (and high sugar). The latter was the health mantra of the 90s - I remember it well! The former is the current craze (think Paleo, Atkins).
The interesting thing from the programme was it confirmed a lot of what I have come to believe. Our bodies NEED sugar. Without sugar, after one month, that twin was medically advised to stop pronto, as he was just about diabetic. He'd lost a lot of weight. BUT a very high proportion came from lost muscle (not at all good). The low-fat-high-sugar diet twin did really well on insulin levels, lost less weight, and lost less muscle...but still lost muscle (not good). So the message they took out of this was that the body needs sugar to function well. And that exercise is absolutely crucial at all times.
Then the show went on to an Oxford researcher who has been doing a large food study for over 10 yrs. Now, that's RARE. (I know of only one other - the mediteranean diet research, which is ongoing.) Her conclusions were that any one thing - she'd varied them all, like low GI, high fibre, low fat, low sugar etc - did virtually nothing to either our weight, or our health. Pretty good news - our bodies are great at adapting and healing. Her conclusion on the weight 'epidemic' was basically that it is environmental, aka, our modern lifestyles make it 'almost impossible not to sleepwalk into obesity' (loved that sentence!). We had to WAKE UP and actively control our food by simply not eating 'treat' foods as everyday foods.
So, then, the next super interesting thing. Especially when you consider our 'treat' foods and foods of modern convenience (environment) seem to break down into this percentage. High sugar was examined in rats. Then high fat. The body just adjusted cleverly to the increases in energy and moderated the appetite - so negligible affect recorded in weight. Then 50/50 fat and sugar was offered. OBESITY was the result. The theory is that at 50%fat and 50%sugar, our brains are tiggered in the same way as when opiods are taken. Pleasure centres triggered, and addiction also, because of the heady response (no pun intended!). The rats also stopped eating nutritional food, and only wanted to eat the fat/sugar mix. (I notice that response in myself if I go down that path - complete lack of interest in anything else but a sugar/fat mix like chocolate!)
I believe that processed food manufacturers know that there is a 'heady' mix that will sell their food (turns out the crispy kreme glazed donut is so popular because it is precisely 50/50 fat and sugar!). I believe all processed foods will have something in them to make us crave them. The 50/50 fat and sugar combination is just one. There are others like MSG, and high fructose corn syrup - which were beyond the parameters of this programme, but have been looked at in others.
So, my take-home...eat stuff that is FOOD. Cook from scratch. Limit your 'treats'. Don't demonise any one thing (if it is food - an additive or chemically made/modified something is not food). Rather simple really!