Crash diet and intense working out at the same time. Will I kill myself?

January 8, 2012 9:56 AM

Has anyone here done Slimfast while doing the Insanity workout?

I want to lose a good 5-10 lbs in the next 4 weeks. So I'm thinking of doing Slimfast and the Insanity workout at the same time. I'll be doing Insanity 6 days a week and slimfast every day. I'm wondering if this is safe to cut calories so much while doing such an intense workout and if I'll even have the energy to do it. I've done each of these things by themselves and lost weight before so I'm thinking if I do both at the same time I'll definitely lose fast in a short amount of time. I'm probably going out on a limb here, but has anyone here done this before or something similar?

posted by daydreamer to Health & Fitness (11 answers total)

Do you mean drinking only Slimfast Or replacing one meal with Slimfast? Could you be more specific about the number of calories you plan to eat and the number you'll be cutting out of your daily diet?
posted by Anonymous at 10:16 AM on January 8, 2012

Response by poster: I plan on replacing 2 meals...the traditional Slimfast plan. This will put me at no more than 1300 calories a day. I have no idea what I eat right now...probably around 1800 to 2000 a day I'm guessing.
posted by daydreamer at 10:19 AM on January 8, 2012

Ah . . . if you were to do it I would start with the Insanity plan maybe 2-3x/week to start. Crash diet + intense workout program is a tremendous amount of stress on the body and a good recipe for failure. Higher chance of you binging due to extreme hunger, getting injured because your body can't recover, and fast weight regain at the end due to your body priming itself for it because of the quick loss and return to old habits that produced the extra fat in the first place.

Depending on how big you are, 5-10lbs/month is a perfectly reasonable goal with a normal, healthy diet and exercise plan.
posted by Anonymous at 10:27 AM on January 8, 2012

As with all things diet-related, YMMV a whole lot, but I lost a steady 2 pounds a week by cutting my carbs to under 50 g per day. Lots of protein, fat, and leafy greens; I was rarely hungry and sometimes had a hard time getting up to 1200 calories a day because I wasn't hungry. I did not exercise (like, pretty much at all). Your proposed regimen doesn't sound great to me, and may well make you pretty miserable and tired, but as a temporary thing it's probably doable and you will probably drop the weight, and probably not injure your body/metabolism permanently.

I am the farthest thing from an expert, and all this is anecdata. My experience may be an outlier.
posted by rtha at 10:39 AM on January 8, 2012 [3 favorites]

Are you trying to be 5-10 lb lighter for a special event in four weeks' time, or do you just have a goal of losing 5-10 lb during this month (and keeping it off)? If it's the former, you can probably drop all of that weight quite easily by switching to a low carb diet about two weeks from now -- depending on your size and current diet, most people lose more than five lb during the first couple of weeks of eating low carb. Another way of dropping weight quickly is doing what's called a "water cut" -- drink a lot of water (up to 1 gallon) every day for up to a week, then stop drinking water entirely ~12 hours before your weigh in.

If it's the latter, Slimfast + Insanity is a stupid combination -- Insanity will make you ravenous, and if you have the willpower to stick to the combo, you'll just end up getting sick or feeling terrible. I echo schroedinger's comment that you could come close to that number with a normal, healthy diet and exercise plan.
posted by telegraph at 10:53 AM on January 8, 2012 [1 favorite]

Agreeing that low-carb is a much safer way to drop weight fast. And moderate exercise is good, but anything more can be counter-productive to dropping weight, since your body will be scrambling to find the resources to build muscle and will hold on to every pound it can.
posted by platinum at 11:05 AM on January 8, 2012

If you're overweight, I agree that diet with only casual exercise is probably the easiest way to do this. Even a normal calorie-counting diet, with no special meals or avoiding carbs or anything... just a lot less of the normal stuff that you eat. (I lost around 8 over four weeks doing exactly this.)
posted by anaelith at 11:24 AM on January 8, 2012

I've spent a fair amount of time on the Insanity forums while doing Insanity (twice), and there is a strong, compelling undercurrent of anecdata posts by people who cutting calories too much and therefore gain weight or otherwise make sub-par progress with the program. The consensus on the forums is, therefore, to follow the Insanity nutrition plans while doing Insanity. The second thing people say on the forums when people ask/complain about weight loss is "are you getting enough calories?" (The first thing they say is: don't look at the scale, your weight doesn't matter and anyway you will gain weight but look fitter because you're gaining muscle.)

1300 calories on Insanity will leave you in worse shape and make you feel terrible.
posted by xueexueg at 6:33 PM on January 8, 2012

Insanity made my husband and I eat MORE food because we expended so many freakin calories on the workout. It was fine because although I didn't lose much weight (maybe 4lbs in 2 months) I lost inches and got awesome muscle definition. But, I would NOT recommend a low calorie diet. The times that I missed lunch and still tried to do the workout when I got home were a disaster because I very nearly passed out from lightheadedness and had to stop.
posted by gatorae at 9:06 PM on January 8, 2012

Response by poster: So glad I asked this question before just jumping into it! Change of plans...no Slimfast. I'm not going to worry so much about cutting calories, but I am going to cut down on carbs, drink lots of water, and eat plenty of protein and vegetables, and do Insanity 4-5 x's a week. The last thing I want is to feel terrible. Thanks everyone for your answers.
posted by daydreamer at 9:27 AM on January 9, 2012

That sounds like a far more effective and sustainable plan. Good luck to you!!
posted by platinum at 1:38 AM on January 10, 2012