Hi I’m a 21 year old man. I’m very healthy in terms of diet and fitness- I eat mostly whole foods, i take a multi vitamin everyday, and work out 3-4 times a week. But recently I’ve been having some medical issues that make me feel old. I’m wondering if maybe there’s an answer.
To start I have been experiencing chronic back pain for a few months. I have no idea why, it feels like it came out of nowhere. I also have been experiencing some extreme fatigue- almost passing out mid class after I shut my eyes. Lastly, I have been experiencing weird mood swings where I go from hyped up/ happy to just completely dead/ sleepy/ sad. There’s a few other things like aches in the morning. And this all started within the last few months. I feel like an old man and I’m only 21! Any help would be much appreciated. Thank you!

So I heard someone say in a group fitness setting that the trainer asked at the very beginning of the session if anyone ate cheese, egg yolks, or whole milk since the last session. A few people said yes and he punished them by making them run laps before doing anything else. That trainer knows nothing about nutrition.

Losing body fat is as simple as being in a calorie deficit, period. You can eat whatever you want, and if you’re still in a deficit, you will lose weight. That's an undeniable fact that has been back by science time and time again.

Plus whole eggs, meaning yolks included, might just be the best super food on the planet.

So be careful who you are getting advice from.

Abstract

Background/Objectives: The gut microbiome is a critical regulator of host metabolism, immunity, and the gut–brain axis. Exercise is a promising non-pharmacological modulator of microbial ecology, yet human evidence remains heterogeneous and the translational gap persists. This narrative review synthesizes mechanisms, human and animal evidence, and future directions for the exercise–gut microbiome axis. Methods: PubMed, Scopus, Web of Science, and SID were searched for articles published between January 2000 and February 2025. Keywords included exercise, physical activity, gut microbiome, gut microbiota, short-chain fatty acids, and gut–muscle axis. From 218 initial records, 89 original studies (47 human, 42 animal) met inclusion criteria and were critically appraised. Results: Exercise modulates the gut microbiome via splanchnic hypoperfusion, hyperthermia, altered transit time, and immune-mediated barrier regulation. Moderate-intensity continuous training consistently increases alpha diversity and enriches butyrate-producing taxa (Faecalibacterium prausnitzii, Roseburia hominis) and mucin-degrading Akkermansia muciniphila. High-intensity interval training transiently increases intestinal permeability in untrained individuals but, following adaptation, stimulates butyrate production via lactate cross-feeding metabolism—a recent breakthrough. Effects are transient and reversible upon detraining. Animal models establish causality through fecal microbiota transplantation; human randomized controlled trials demonstrate modest, intensity-dependent, and highly individualistic responses. Emerging evidence supports the gut–muscle axis in sarcopenia and personalized exercise prescription guided by microbiome profiling. Conclusion: Exercise shows promise as a low-cost modulator of the gut microbiome for enriching health-associated taxa and improving metabolic outcomes. Definitive evidence linking exercise-induced microbial shifts to enhanced athletic performance in humans remains lacking. Future research requires diet-controlled randomized controlled trials with ≥12-week interventions, shotgun metagenomics, and mechanistic validation of the gut–muscle axis in humans.

A step counter will not do the hard part of dieting for you. But new research suggests it may help with the part many people struggle with most, keeping the weight off once it is gone.

I want it to function like a deck of cards where I can randomly choose a card. On that card will have an exercise or movement.

However, instead of one deck of cards it should be dozens of decks, each full of movements based on specific categories.

For example:

- Pilates Deck: reverse sit ups, 100, clam shell, etc.

- Cardio Deck: burpees, jumping jacks, high knees, etc.

- Lower Body Deck: sumo squat, bridge, side lunge, etc.

And so on and so on. Then I can choose from the decks I want shuffled together. So I might get a cardo activity or I might get lower body.

Then, and this would be amazing, I want the option to have it give me a notification of a movement at preset increments. So maybe every 1.5 hours I’ll get a notification that says: 5 Burpees, or 1 min plank, etc.

Does this exist? And if not, will someone please make it!

Abstract

Background

Caloric restriction (CR), achieved by reducing energy intake without malnutrition, has been shown to preserve muscle function and delay age-related declines in strength and mobility by modulating key metabolic and molecular pathways involved in muscle maintenance. While most initial research on CR was done in rodents, non-human primates (NHPs) offer a higher translatable animal model for understanding CR effects due to their close genetic, physiological and cognitive similarities to humans.

Methods

In this cross-sectional study, we investigated skeletal muscle gene expression changes induced by 30% CR in skeletal muscle in rhesus monkeys (n = 18 CR, n = 18 control). We performed high-depth RNA sequencing to profile gene expression and alternative splicing variants and identify pathways linked to aging, regeneration/degeneration, and energy metabolism.

Results

Transcriptomic profiling revealed widespread gene expression differences between CR animals compared to controls. Genes that were overexpressed were mainly involved in pathways related to energy metabolism, mitochondrial function, signaling, and oxidative stress response. Conversely, underexpressed genes were connected to immune response, extracellular matrix organization, apoptosis, and ribosomal RNA processing. Further, we identify alternative splicing as a major mechanism by which CR modulates genes involved in muscle function, metabolism, and aging.

Conclusions

Caloric restriction preserves skeletal muscle by enhancing metabolism, limiting degeneration and inflammation, and engaging conserved mechanisms across species.