A Final Word of Warning: As mentioned earlier, having a high level of fats in the body, even beneficial ones, can lead to weight gain, and considering that many people will associate macadamia nut oil with the nuts themselves (which have a shocking 718 calories per 100 grams), they may indulge and see some weight gain as a result. Also, macadamia nut oil has been known to cause constipation in limited cases. Finally, for those who suffer from nut allergies, the extracted oils don’t always cause allergic reactions, but in some cases, a similar allergic reaction can occur. Consult a medical professional before making any major changes to your diet, health supplement regimen, or cooking style.