Two SureSlim clinics, which have opened in Scotland, provide an eating plan to make sure that women do not put on more than one or two stone during pregnancy and can shed any extra pounds immediately after the birth if they 'control' their eating.
The diet plans, which cost 495 pounds, include one-to-one consultations with the firm's experts, diet advice sheets with lists of approved foods, and blood tests to check for health problems.
So far, the private firm has treated 'hundreds' of pregnant women at its clinics south of the border and has now opened branches in Perth and Edinburgh.
Some women try to avoid even natural weight gain, a condition dubbed 'pregorexia', and that many pregnant women feel pressurised to regain their figures quickly after childbirth.
However, nutritionists have warned that dieting during pregnancy could result in major health problems, saying pregnancy was 'not a time for slimming'.
The SureSlim diet is based on balancing hormone levels in the body to encourage it to burn fat.
"This has good, solid medical backing. We have not reinvented the wheel. For pregnant women it's about controlling what they eat, not about losing weight. It means that during the pregnancy they will gain about one to two stone rather than three to four," the Scotsman quoted Daryl Taylor, chief executive of SureSlim, as saying.
While putting on too much weight during pregnancy can lead to health problems for mother and baby, gaining too little weight during pregnancy is linked to poor foetal growth, lower birth weight and the chance of a baby being born prematurely.