The importance of a well-balanced diet during pregnancy : Macronutrients

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This article is the first one of a serie about pregnancy that is going to be published throughout this month of December and maybe January too. Why ? Because the coldest  months of the year are the most productive ones when it comes to baby conception… 😉

Everyone knows that following a well-balanced lifestyle, which means a diet filled with high-quality nutrients, is the most essential element to help our body stay healthy as long as possible.

But do you know that you could be predisposed to some diseases because of what your mother ate when you were only a fetus inside her belly ? Keep reading and you could surprised how much food is significant during pregnancy for both child and mother.

284.2 days is the average duration of a pregnancy. A period during which the corpus luteum (process of hormonal production inside ovarya) and the placenta increase progressively the concentration of progesterone (steroid hormone involved in the female menstrual cycle, pregnancy and embryogenesis of humans and other species) and estrogens (the primary female sex hormones). The increase of hormonal concentration during pregnancy contributes to the changes in nutrient metabolism induced by the fetal demands and the maternal nutrient supply. A limit exists in the physiological capacity to adjust to the increase in  nutrients consumption necessary to meet pregnancy needs. This limit shouldn’t be exceeded, to avoid impairing fetal growth and development.

During the first trimester a woman should gain between zero to two kilograms (zero to four pounds). Even though the fetus does not grow very much, the diet should already be adapted, with a proper nourishment and nutrient supplementation (vitamins and minerals), because it may have a significant impact on the outcome of pregnancy.

When it comes to the second and third trimester, the healthy average weight gain for a pregnant woman is between 0,4 to 0,5 weight gain kilograms (0,9 to 1,10 pounds) per week. With a maximum total weight gain between 9,6 to 12 kilograms (20 to 26,5 pounds) at the delivery. This weight gain is not only explained by the development of the fetus but also by the growth of the placenta, the amniotic fluid, the weight increase of the uterus, the breast and the blood volume, but mostly by the maternal stores of fat, protein, water and other nutrients.

How should weight gain happen ?

Starting the second trimester, it is suggested to augment the energy intake of 180 calories per day, and then add eight calories each new week. To finally end up with 450 additional calories per day added to the  basic 2200 calories (average caloric intake for an non-pregnant healthy woman), which represent a daily addition of 20%.

Macronutrients chart child drawFor the reminder, one dietary calorie is the amount of energy needed to raise the temperature of one kilogram of water by 1°C. The recommended intake of each energy-yielding nutrient, as a percent of total calories, is as follows : 45% to 65% of carbohydrates, 20% to 35% of fats and 10% to 35% of proteins.

Determination of nutrient needs during pregnancy is complicated, because of the huge change that happens to the maternal metabolism which could differ from an individual to another depending on the weight, age, and environment… but scientific and statistic studies furnish clear correlations between maternal nutrient intake, pregnancy complications and reproductive outcomes.

Macronutrients :


Providing the body’s primary and preferred source of fuel for energy, carbohydrates also maintain the body’s backup store of quick energy as glycogen. But the most important is the quality of the carbohydrates. One should favor full calories (fruits, vegetables, starches) instead of empty calories (candy, processed food), because full calories will, in addition, supply the body inbaby in a lettuce basket fibers, vitamins and water.

The carbohydrates metabolism is altered during pregnancy, and the pregnant state has been characterized as diabetogenic (that can result in diabetes). The maternal metabolism fuels the fetus almost exclusively with glucose and he uses it at a rate of 6 milligrams per kilogram per minute at term. In comparison to an adult, who uses it at a rate of 2,5 milligrams per kilogram per minute. This shows the importance of the increase of carbohydrate ingestion throughout the pregnancy. Moreover, if the diet is correctly balanced the diabetogenic risk is restrained.

Furthermore, the supply of fiber through carbohydrate foods, helps to regulate the passage of food material through the gastrointestinal tract. A crucial need for pregnant women, whose gastrointestinal system is perturbed due to hormones changes, resulting in constipation.


Providing the amino acids that are necessary for building and maintaining body tissues, proteins are divided in two groups : complete and incomplete.

The complete proteins contain at least nine amino acids classified to be indispensable because the body cannot manufacture them in sufficient quantity or at all. They are found mostly in animal based foods such as eggs, dairy products, meat, poultry and seafood but also in some plant based foods like soy products (good substitute for the lactose intolerant and the vegan) and quinoa (in small amount).

The incomplete proteins are made of some of the essentials amino acids as well as some unessentials or semi essentials amino acids (that the body can manufacture). They are found mainly in plant based foods such as grains, legumes, nuts and seeds.

Regarding the pregnancy state, proteins are needed to support the development of the placenta and are used by the maternal body’s metabolism to rapidly grow the fetus and the maternal tissue (support pregnancy, lactation, and the uterus and breast tissue), as well as to increase maternal blood volume (plasma volume increases by 40% to 50% and is necessary for nourishing the fetus and supporting the increased metabolic workload), and increase amniotic fluid (which contains various proteins) which role is to protect the fetus against shock or injury.

Thereupon, a 21 day study following three groups of women : four early pregnant (EP) women, four late pregnant (LP) women and six non-pregnant (NP) woman, whom were between 20 to 35 years old, who were following healthy lifestyles, were non-smoker and were on the same omnivorous diet, showed that amino acids are conserved for tissue synthesis in LP women. But there is no evidence that pregnant women store protein earlier in the gestational period. So the increased dietary requirements of LP women must be met by physiologic adjustments that enhance dietary protein utilization. This shows that maternal nutrient supply influences the physiological response to pregnancy.

Nevertheless, there still is a recommended protein intake throughout pregnancy. To cover the daily 21 gram protein deposit in fetal and maternal tissue during the second and the third trimester, it is necessary to increase the recommended protein intake of 1 gram of protein per kilogram of bodyweight.

But still, keep in mind, that several factors (physical activity, age, weight…) should be considered regarding the amount of protein intake (in example : an active pregnant woman should ingest more proteins than a sedentary pregnant one).


Found in both animal and plant sources, fats provide the body’s secondary form of stored energy (carbohydrates being the first one). It also satisfies important tissue needs as a structural material for cell membranes, a protective padding for vital organs, and insulation to maintain body temperature, as well as covering for nerve fibers.

There are two main sorts of fats : Saturated fats which primarily come from animal food sources (meats, dairy products, eggs), that could, when eaten in excess, carry health risks for the body and contribute to several risk factors which include obesity, diabetes, elevated triglycerides, and elevated blood pressure. However, when it comes to saturated fat, coconut oil and cocoa butter seem to be healthier fats than animal based fats.

Unsaturated (poly and mono) fats which are found in seafood and plant based foods (avocados, seeds, nuts, olives), may reduce health risks when used in place of saturated fats.

Omega-3-Fatty-AcidsTwo third of the daily fats consumed should be from plant sources and obviously one third from animal sources.

Indeed, aside from the fact that saturated fat consumption in excess is bad, a fat-free diet may lead to essential fatty acids deficiency with clinical manifestations. Omega-3 (fish oil) fatty acids are specially important for brain function, the central nervous system, and the cell membranes. Low levels of omega-3 and omega-6 fatty acids are linked to hair loss, low blood platelet levels (which pregnant women are already subject to, because of hormonal changes), impaired vision, compromised brain function, and growth retardation in children.

Now that we have a better vision of the main nutrients in our diet, we can better understand how important a miscellaneous diet, rich in good quality products is, and what a difference  it can make for the mother’s health and her child’s.

However, it does not end here. To be used and synthesized properly, macronutrients need to be processed by the body, which needs help from micronutrients (vitamins & minerals) to accomplish that task.

So, as you probably guessed, micronutrients intake throughout pregnancy is the subject we will dive into in our next article of the pregnancy serie.




References :

1.Physiology of pregnancy, by Mel. C. Barclay

2.Dietary supplement use in women : current status and future directions, by Mary Frances Picciano – 2003

3.Physiology of pregnancy and nutrient metabolism, by Janet C. King – 2000

4.Maternal nutrition during pregnancy and health of the offspring, by M.S. Martin-Gronert & S.E. Ozanne – 2006

5.Williams’ Basic Nutrition and Diet Therapy – 14th edition, Stacy Nix – 2013

6.Parent-Offspring Conflict and the Persistence of Pregnancy-Induced Hypertension in Modern Human by Hollegaard B, Byars     SG, Lykke J, Boomsma JJ (2013)

7. HCG and Hyperglycosylated HCG in the Establishment and Evolution of Hemochorial Placentation by Cole, Laurence A Journal of Reproductive Immunology 82.2 (2009




4 thoughts on “The importance of a well-balanced diet during pregnancy : Macronutrients

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  2. Pingback: The importance of a well-balanced diet during pregnancy : Micronutrients | EveryDayLife Performance

  3. Pingback: The importance of a well-balanced diet during pregnancy : Preventable risk factors | EveryDayLife Performance

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