Tuesday, August 6, 2013

How To Get Rid Of Pregnancy Weight? Exercise, Diet Or A Combination Of Both? What Works And Is Safe? Plus: Full Breastfeeding Alone Sheds 12kg of Pregnancy Weight

Mother's love is a natural instinct, the worries about pregnancy weight not, simply because it would hardly ever occur in nature. If anything you'd be worried not to "make" enough weight to nurture your baby after the pregnancy.
If the name “Cochrane review” does not ring a bell, let me briefly fill you in on what the Cochrane Database and the Cochrane reviews are, before we are delving deeper into the topic at hand, which is, or rather which are the results of the latest Cochrane Review on “Diet or exercise, or both, for weight reduction in women after childbirth” by Amorim Adegboye & Linne YM (2013).

I guess, the elevator pitch on what distinguishes Cochrane Reviews from the rest of the pack, would read as follows: They are comprehensive, they are systematic, they review only primary research in human health care and health policy, and they are internationally recognized as the highest standard in evidence-based health care.  When you’ve read one, you should know what the effects of interventions for prevention, treatment and rehabilitation and how reliable the actual results presented are.

Ok, that’s my assessment, now let’s see what the Cochrane Foundation says about their own work:
“Each systematic review addresses a clearly formulated question; for example: Can antibiotics help in alleviating the symptoms of a sore throat? All the existing primary research on a topic that meets certain criteria is searched for and collated, and then assessed using stringent guidelines, to establish whether or not there is conclusive evidence about a specific treatment. The reviews are updated regularly, ensuring that treatment decisions can be based on the most up-to-date and reliable evidence.”
Sounds similar, right? Now, although they certainly have a high standard and are internationally acclaimed for that, this does not protect these review from being subject to scientific bias, themselves and it’s quite normal to get at least 10 rebuttals to rebuttals after one of these reviews is published. Still, I guess the 77 page report from which I will pick just the most important facts for you is at least the most comprehensive review of the post-pregnancy weight-loss I’ve come across up to now.

Enough of the foreplay let’s get right to the time after the pregnancy now ;-)

So guys - I am deliberately addressing YOU, because you usually don’t care how, just that your significant other gets back in shape - what are you supposed to do if you just became a daddy? If you did everything right during the pregnancy and did not support your wife’s tendency to finally overeat after years of chronic starvation, you are already in a pretty good starting position. Otherwise, you and your wife or girlfriend are probably going to have a rough time to get her back in shape. So…

A. To diet or not to diet?

Assuming that you did not support the nutritional super-size escapades of your significant other during the pregnancy you are best advised to keep her from restricting her food intake.

The latter would probably increase the weight loss (-1.7kg), but most of this weight loss would come from lean mass and would set your wife or girlfriend up for the notorious yoyo effect, or life-long dieting; and that for a meager -0.4% less body fat and at the expense of a reduction in breast milk volume of -18g/day.

B. To work out or to sit still?

You don't have to lie around and eat 24/7, just because you are pregnant: 85 sessions (general fitness class, three times/week, 55-60 min/session from weeks 8-10 to weeks 38-39 of pregnancy are nothing but healthy for mother + child (learn more)
While it is not necessary for weight loss in breast feeding women, it is certainly necessary for your significant other’s overall health, fitness (+6.73mL/kg VO2Max) and lean mass (+0.88kg). Just keep her away from arduous hours of cardio exercise if you don’t want your baby to starve or your wife / girlfriend being forced to fed him/her formula and thus set your offspring up for metabolic and immune problems in the future.

While not being significant the Cochrane review still reports a trend for greater reductions in body fat percentage (-2.51%) for women who worked out in the post-partum period. And while it was beyond the scope of this review, SuppVersity readers will be aware that working out offers protection against post-partum depression, as well (Dennis. 2013).

As mentioned above doing too much entails the risk of reduced milk production and thus depressed infant weight gain. Both were yet not found to be statistically significant and occurred only in some of the pertinent studies.

C. What about working out & dieting

Contrary to dieting alone this is a very favorable approach to get rid of the pregnancy weight. In fact, the likelihood of returning to pre-pregnancy weight was doubled in the three trials that investigated the effects of combined exercise and diet programs. The chances to get back to a health weight after crazy pregnancy binges was even four times higher!

Against that background it is not surprising that we see an overall -1.93kg increase in body weight loss and -2.19% higher losses of body fat in women who diet and work out (sanely) after their pregnancy. The fat free mass loss observed with diet alone was not an issue and most importantly the volume of breast milk, infant length growth and infant weigh gain increased (probably alongside the mother’s health).

Figure 1: Pregnancy-weight left (in kg) in Danish mothers breastfeeding for different time periods 6 months after the baby was born; the x-axis indicates the pregnancy weight gain in kg (Baker. 2008)
So what are the implications for mother's and fathers to be? For the guys, I would say you better make sure to keep the fridge well-stocked with fresh healthy foods to nourish your family and be prepared to watch for the kid (or kids if this is not your first-born), while your wife is at the gym.

For the ladies, on the other hand, it’s actually quite simply. Just eat a clean diet, work out regularly, not arduously and endlessly and by all means, breastfeed your baby. That alone has been shown to suffice to eliminate up to 12kg of pregnancy weight during the recommended 6-months period of exclusive breast feeding in a 2008 study from Denmark (Baker. 2008)

And lastly don't put yourself under too much pressure. Better slow and steady, than fast and failure-prone. 

  • Baker JL, Gamborg M, Heitmann BL, Lissner L, Sørensen TI, Rasmussen KM. Breastfeeding reduces postpartum weight retention. Am J Clin Nutr. 2008 Dec;88(6):1543-51.
  • Dennis CL, Dowswell T. Psychosocial and psychological interventions for preventing postpartum depression. Cochrane Database Syst Rev. 2013 Feb 28;2:CD001134.