Intermittent fasting strategies and their effects on body weight

Overall interpretation of the study

• Many see the “longer trials needed” language as partly signaling a funding need, not just scientific caution.
• Core takeaway: alternate-day fasting (ADF) leads to weight loss and may slightly outperform equivalent continuous calorie restriction, though the basic “eat less → weigh less” result is unsurprising to many.

Intermittent fasting vs simple calorie restriction

• Several comments emphasize that if ADF averages the same weekly calories as daily restriction, weight loss is similar; the paper’s nuance is that ADF may yield marginally more loss.
• Supporters argue that fasting may activate distinct pathways (mTOR, autophagy) beyond linear calorie math and could affect longevity.
• Others stress that the main benefit of IF/ADF is making restriction easier to adhere to, not magic timing.

Body composition, lean mass, and protein

• Concern: weight loss metrics ignore whether loss is fat vs lean mass; losing muscle is especially risky for older adults.
• Counterview: for obese people, total weight/fat loss dominates other concerns.
• Consensus that any deficit risks lean mass loss; adequate protein and resistance training are needed.
• Debate on how to calculate protein needs (actual vs ideal/adjusted body weight), with citations for using ideal or adjusted weight in obesity.

Calories in / calories out and metabolic complexity

• One camp insists thermodynamics is decisive: sustained deficit always leads to weight loss; timing or diet type mainly help psychology.
• Others argue this framing is “true but useless” because:
  • Energy expenditure adapts to intake (NEAT, body temperature, hormonal changes).
  • People misestimate calories in and can’t measure calories out precisely.
  • Crash deficits can provoke long-lasting metabolic compensation and regain.
• Disagreement over how large adaptation effects are and how actionable CICO is in practice.

Psychology, habits, and practicality

• Many see IF as a habit-reset tool:
  • Breaking automatic breakfast/snacking.
  • Learning that hunger signals are tolerable and not emergencies.
• Coffee-with-milk during “fasts” sparks minor purity debates; some prioritize strict rules, others prioritize sustainable behavior change.

Exercise vs diet

• Strong theme: you “can’t outrun a bad diet”; exercise often increases appetite and burns fewer calories than people think.
• Others report large endurance volumes (running/cycling) allowing very liberal eating, but this is framed as niche and time-intensive.
• For modest weight loss, some argue exercise helps mood and adherence; others emphasize portion control as primary.

Fasting, health, and longevity

• Some clinicians and commenters use IF within broader longevity strategies and note macaque and animal data on fasting benefits.
• Discussion of fasting around chemotherapy and long fast anecdotes (including extreme multi-day fasts) suggest possible autophagy and immune effects, but commenters flag that much evidence is animal-based and human relevance is still unclear.

Anecdotal outcomes and alternative strategies

• Multiple N=1 stories:
  • Long-term 16:8 IF with stable weight but perceived mental clarity.
  • Extreme IF patterns (23:1, alternate-day) with substantial weight and fat loss.
  • IF combined with keto producing dramatic losses and appetite suppression; carb restriction cited as making IF “trivially easy.”
  • Others lose large amounts via skipping specific meals plus tracking macros, then later drop IF due to blood sugar issues.
• Some frame IF mainly as one structured system among many (keto, low-carb, etc.) that can help people who struggle with unstructured “just eat less” advice.