Is weight loss healthy when you're pregnant?  

Rebecca McPhee
Dietitian Member of the DAA


3 Minutes

 

No doubt at some point there has been some talk about pregnancy weight. How much will I gain? Will I put on too much? When will I need to start buying bigger clothes? Is it safe to shed a few kilos? That is a lot of pressure to add to the rest of the long list of considerations, don't you think?!  

Gaining weight during pregnancy is completely natural and a vital part of your baby’s development and preparation for your body for breastfeeding. Trying to lose weight whilst you are pregnant is not recommended. Intentionally trying to lose weight means that you may miss out on important nutrients needed for growth and development.   

It doesn't mean that we don't watch our weight and start eating for two! We know from research that gaining too much weight during pregnancy and too quickly increases your risk of health problems including diabetes during pregnancy, called Gestational Diabetes, high blood pressure and having a caesarean. Studies have shown that even for women in the healthy weight range, a weight gain of more than 2.5% of their body weight prior to pregnancy was associated with 2.7-times higher risk of developing gestational diabetes compared with healthy weight women who did not gain any weight. Gestational diabetes also increases your risk of developing type 2 diabetes in the future by 50%. 

So the quesiton should not be 'how much weight can I lose?' but 'what is considered a healthy amount of weight to gain during pregnancy?' 

 

How much weight can I gain during pregnancy? 

The right amount of weight you gain during pregnancy is not a one size fits all approach. It really depends on your BMI (Body Mass Index) before pregnancy. The general rule is that if you are above a healthy weight before pregnancy, you should aim to gain less weight than those who are a healthy weight. Your BMI is calculated as your weight (kg) divided by your height (m)².  

 

Below are recommendations from the Institute of Medicine for total and rate of weight gain during pregnancy, by pre-pregnancy BMI: 

 

Pre-pregnancy BMI 

Total weight gain in kg 

Rates of weight gain* 2nd and 3rd trimester in kg/week 

Underweight (< 18.5 kg/m2) 

12.5 – 18.0 

0.51 (0.44 – 0.58) 

Normal weight (18.5 – 24.9 kg/m2) 

11.5 – 16.0 

0.42 (0.35 – 0.50) 

Overweight (25.0 – 29.9 kg/m2) 

7.0 – 11.5 

0.28 (0.23 – 0.33) 

Obese (≥ 30.0 kg/m2) 

5.0 – 9.0 

0.22 (0.17 – 0.27) 

Weight gain during pregnancy: recommendations for Asian women, by pre-pregnancy BMI 

Pre-pregnancy BMI 

Total weight gain in kg (during pregnancy) 

Weight gain per week in kg (after 12 weeks) 

<18.5 

12.5-18.0 

0.5 

18.5-22.9 

11.5-16.0 

0.4 

23-27.5 

7.0-11.5 

0.3 

>27.5 

≤ 7.0 

  

Reference: Institute of Medicine, 2010 

 

Lifestyle tips if you are above a healthy weight 

If you are above a healthy weight, don't panic! Look at your 9 months of pregnancy as an opportunity to adopt healthy eating habits that you can continue once the baby is born. Continuing with a healthy eating plan after the baby is born will also help you to shed those post baby kilos.  

One study found that women who received diet and lifestyle advice between weeks 7 and 21 of pregnancy were less likely to gain excess weight during the third trimester. The Capital Chicks CANberra have loads of ideas to help you adopt a healthy lifestyle. However, if you would like more personalised advice, ask your GP for a referral to an Accredited Practising Dietitian.  

 

1. Follow the Australian guideline to healthy eating for pregnancy 

 

Food Group 

Number of serves 

Example of serving size 

Vegetables, legumes/beans 

½ cup cooked vegetables  
½ cup cooked or canned* beans, peas or lentils 
1 cup green leafy or raw salad vegetables 
½ cup sweet corn 
½ medium potato or other starchy vegetables  
1 medium tomato 

Fruit 

1 medium fruit, such as apple, banana, orange 
2 small fruits, such as apricots, kiwi fruits or plums 
1 cup diced or canned fruit (no added sugar)  

Grain (cereal) foods, mostly wholegrain and/or high-fibre varieties 

8 1/2  

1 slice bread, ½ medium roll or flat bread (40 g) 
½ cup cooked rice, pasta, noodles, barley, buckwheat, semolina, polenta, burghul or quinoa 
½ cup cooked porridge, 2/3 cup wheat cereal flakes, ¼ cup muesli 
3 crispbreads 
1 crumpet, small English muffin or scone 

 

Lean meats and poultry, fish, eggs, tofu, nuts and seeds and legumes/beans 

 

3 1/2  

65 g cooked lean meats, such as beef, lamb, veal, pork, goat or kangaroo  
(90–100 g raw) 
80 g cooked lean poultry, such as chicken, turkey (100 g raw) 
100 g cooked fish fillet (115 g raw) or one small can of fish 
2 large eggs 
1 cup cooked or canned* legumes/beans, such as lentils, chickpeas or split peas 
170 g tofu 
30 g nuts or seeds, nut/seed paste* 

 

2. Have a plan 

Do you ever find that when you go to the supermarket without a shopping list, a lot of the non essentials come back with you?! Write out a shopping list before you go and plan a week's worth of meals. You will be surprised at how much money you will also save! 

 

3. Watch the extras 

Discretionary foods, often called 'sometimes' or 'treat' foods are where the kilojoules can pile up and contribute to extra weight gain. Discretionary foods are high in saturated fat and sugars and should be kept to occasioanlly. Basing your diet around the 5 food groups and planning meals will leave little room for temptation!   

  

4. Get moving 

Including daily physical activity during pregnancy is completely safe as long as you exercise with caution and don't overdo it. Regular physical activity is important for your physical health and wellbeing. Aim for at least 30 minutes most days. 

 

5. Monitor your weight 

Use the weight calculator guide to monitor your weight. It is not uncommon for some women to lose weight during the first trimester due to morning sickness. Your Doctor will monitor this and if you are struggling to gain the recommended weight for your BMI, an Accredited Pracitising Dietitian can provide you with the advice you need. 

 

6. Positive mindset 

 

Enjoy your pregnancy and focus on nourishing yourself and your baby with quality nutrient dense food. Getting out into the fresh air or practising some meditation will also help to calm a worried mind and keep you grounded.  

 

In summary 

  • Weight loss during pregnancy is not advised as it can put your baby at risk of missing important nutrients needed for growth and development  

  • Preventing too much weight gain should be the focus  

  • Gaining too much weight and too quickly can increase your risk of developing gestational diabetes, high blood pressure or having caesarian  

  • Monitor your weight with the guidelines set by the Institute of Medicine 

  • Focus your diet around the five food groups and include daily physical activity 

 

References 

  • Adane, A, Tooth, L and Mishra G. Pre-pregnancy weight change and incidence of gestational diabetes mellitus: A finding from a prospective cohort study. Diabetes Research and Clinical Practice. Volume 124, P72-80, February 01, 2017 
  • Akilew Awoke Adane, Leigh R. Tooth, Gita D. Mishra. Pre-pregnancy weight change and incidence of gestational diabetes mellitus: A finding from a prospective cohort study. Diabetes Research and Clinical Practice, 2017; 124: 72  
  • IOM recommendations for weight gain in pregnancy. Institute of Medicine, 2010 
  • Kimberly K. Vesco et al Obesity, A Research Article, Volume 22 Issue 9, PP1989-1996, 28 August 2014. Efficacy of a group‐based dietary intervention for limiting gestational weight gain among obese women: A randomized trial 
  • www.eatforhealth.gov.au 

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