Without harming your health, and ignoring magic, if you are a male, 37, out of sports for several years, slightly overweight, but willing to work hard in these 6 weeks for personal reasons.

How much could he change his body?

  • 1
    You could expand on your question, to include what kind of sports history you have and why the timeline. For example, my answer would differ if you were a former collegiate level athlete looking to get back into shape quickly, versus an intramural player that wants to look good in a tux for his kid's wedding. :)
    – JohnP
    May 17 '18 at 20:10

Everything being ideal, you might expect to lose 6 lbs of fat and put on 3 lbs of muscle. To achieve this, you’ll want to do some LISS cardio (ie taking a long walk) everyday as well as doing strength training and HIIT cardio. You’ll also want to eat in a (roughly estimated) 300 calorie deficit off of your TDEE, and get plenty of protein (maybe up to 1 gram per pound). Supplementing with Creatine may also give a slight boost to muscle mass appearance, so that may be worth a shot for that alone , but beyond that it will also help to improve performance.

Quick Reference Guide for the Acronyms...

  • LISS "Low Intensity Steady State", a type of cardio training that usually requires more time than intensity.
  • HIIT "High Intensity Interval Training", a type of cardio training that usually requires more intensity than time.
  • TDEE "Total Daily Energy Expenditure", this represents how many calories you burn in a day through a combination of physical activity (both exercise and typical day to day movements) and basal metabolic rate.

A couple notes...

  • LISS may be done every day due to the relatively low demands it places on the body. HIIT and Strength Training are different.
  • Strength Training sessions should ideally last less than an hour. Just keep your rest times in check, and your exercise load reasonable. If you end up going over, it's not going to kill you, but just know that it there are downsides to doing so.
  • HIIT sessions should ideally last 30 minutes or less. My suggestion would be to do HIIT and Strength Training on separate days to prevent overtraining.
  • "Creatine Loading" can cause a lot of problems, just stick with 5 grams a day and after about a month you should be seeing the full benefits of it.
  • 1
    For readability by people new to fitness, could you expand on the acronyms?
    – JohnP
    May 17 '18 at 20:09
  • You might want to explain that adding creatine has a tendency for people to retain water initially. I’ve seen as much as 3-5 pounds of water weight with creatine which gives the illusion of backwards progress for some
    – Frank
    May 17 '18 at 20:10

Well, if all you’re planning on is 6 weeks of hard work, you might as well not even start. I was in the exact same position as you a few years ago, but I was 33 instead of 37. The first 6 weeks? I was just feeling my way around the weight room, understanding at a slow pace what my body was capable of, and formulating a diet I could stick with for the rest of my life.

So, truth be told, I don’t think I lost anything in the first weeks. Look, just like exercise, diet requires somewhat of a slow gradual buildup too. You can’t just slam your body full throttle into some rapid opposite. The chances of failure are just too high.

If you’re going to “get fit” you need to think much longer term. Fitness and health and even weight loss is not something that comes in a few weeks. Sacrifice the short battle for the long term war.

I recommend in the next six weeks to dabble with every piece of gym equipment, perform all the various cardio exercises you want, and find the “things” that interest you. Say you really like weightlifting but not the cardio stuff: Then focus on your “major” being weightlifting with a “minor” in HIIT.

Figure out what will keep you coming back in the next six weeks and train for that from there. Your tastes may change as you progress, but you’ll feel a lot less like you’re just going through the motions, and a lot more like fun. When you’re having fun, your intensity goes up and you make more gains. It’s that simple.

What can you expect maybe in 12 weeks assuming the first 6 weeks is experimentation? A rough FAT loss of about 6-12 pounds and maybe a pound or two of newbie muscle gains. That is provided you keep your diet in check.

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