Severely restricting carbohydrates to less than 0.7 ounces (20 grams) a day can result in a process called ketosis. Ketosis occurs when you don't have enough sugar (glucose) for energy, so your body breaks down stored fat, causing ketones to build up in your body. Side effects from ketosis can include nausea, headache, mental and physical fatigue, and bad breath.
However, there’s no evidence that following a low-carb diet is any more beneficial in managing diabetes than other approaches in the long term, including a healthy, balanced diet. Research suggests that the best type of diet is one that you can maintain in the long term, so it's important to talk to your healthcare professional about what you think will work for you. Another option is the Mediterranean diet, which is also linked to reducing the risk of heart diseases and stroke.
Healthy fats & oils are back in too: Eating fat does not automatically clog the blood vessels in the way that poring oil down the drain will eventually block the drain. You make your own cholesterol and lipids and are more likely to increase your levels of the more damaging Very Low Density Lipoprotein (VLD), which is made in the liver when you eat a high carbohydrate diet.