Intermittent fasting works – not only for weight loss but also for heart health

You can say this about literally any food. Nonsense.

A lot of what I've read over the past few years suggests that exercise won't help you lose weight[0]. It's great for general health, but exercise without some kind of diet modification generally won't do all that much for your weight.

This tracks with my experience, at least. In early 2016 my doc told me I needed to get some exercise. At the time I was doing nothing more than walking to and from work (60 mins total). I started running, and worked up to around 10 miles per week. I'd already been more or less been doing IF for a while (without realizing it; I was just never hungry when I woke up), eating lunch at noon and dinner at 7pm, or just a single mid-afternoon meal around 3pm.

I didn't start actually losing weight until 2 years later, when I started calorie counting and attempting to limit my intake to around 1500 per day (I wasn't always successful). It was still difficult; I only lost 6 or 7 lbs, and it took nearly a year to do that.

That turned out to be hard to maintain; I stopped counting calories, and by late 2019 I'd put those lbs back on and probably a couple more, even with IF in place.

With COVID-19, I've been cooking 6 days a week, so that's meant less oil/butter, nothing fried, but still a good amount of carbs. My running has dropped to 4-6 miles a week. But in less than three months, I've lost 15 lbs. The only thing that actually worked was changing my diet. Once things go back to normal and I'm going out to restaurants again, I fully expect I'll put that weight back on.

[0] E.g. https://www.vox.com/2016/4/28/11518804/weight-loss-exercise-...

This phrasing is too easily misinterpreted.

Saying "works" leaves ambiguity between outcomes (i.e. weight loss results) and processes (i.e. metabolic mechanisms and changes). If you said "IF showed similar results as CR in treating obesity" that is consistent with the paper.

Second, saying "exactly like" in the context of statistics is an effective way to invite criticism (and not the constructive kind).

From the key points on the front page:

  > The heterogeneity in the current evidence limits
  > comparison of IF to other weight-loss strategies.
  > Intermittent fasting shows promise as a primary care
  > intervention for obesity, but little is known about 
  > long-term sustainability and health effects. 
  > Longer-duration studies are needed to understand
  > how IF might contribute to effective weight-loss
  > strategies.

The key of any weight-loss diet is that it somehow hacks our brain so that we end up eating less. But everyone’s brain is different, so different hacks work (or not) for different people. That’s why you have so many diets - fasting, intermittent fasting, keto, paleo, zero carb, low fat, food separation diet, ...

Personally, intermittent fasting hasn’t helped me lose weight (might have helped me maintain it though). So far, the only thing that has helped was very strict calorie counting, but that was accompanied with severe emotional/mental discomfort (constant hunger). I’m now experimenting with one-day fasting (turns out not eating, for me, is associated with less hunger than eating too little, go figure ...), we’ll see how t goes.

"there's no magic to IF"? Well, literally speaking, I tend to agree. For example, I've never actually made out any mustachioed magical monkeys monkey-patching methods in Ruby on Rails.

Seriously though, I think I disagree with the intent behind your sentence, which I interpret as downplaying the difference between IF (intermittent fasting) and CR (calorie restriction). Based on reading the Obesity Code, my understanding is that IF leads to substantially different biological responses relative to CR.

This diagram below, or something similar to it, is a nice way of understanding the core principles in The Obesity Code by Fung which promotes IF. Sustained durations of fasting help lower insulin levels for long enough periods that insulin resistance itself can lower. (CR doesn't do this, to my knowledge.)

  ASCII Diagram version of
  https://thefastingmethod.com/wp-content/uploads/HOT-Fatty-Liver2.1.jpg 

                         ┌────────┐                       
  ┌───────────┐          │  high  │          ┌───────────┐
  │  glucose  │────┬────▶│insulin │────┬────▶│  obesity  │
  └───────────┘    │     └────────┘    │     └───────────┘
                   │                   │                  
                   │                   ▼                  
            ┌────────────┐      ┌─────────────┐           
            │  insulin   │      │    fatty    │           
            │ resistance │◀─────│    liver    │           
            └────────────┘      └─────────────┘           
                                       ▲                  
                                       │                  
                                       │                  
                                ┌────────────┐            
                                │  fructose  │            
                                └────────────┘