This method, of no refined sugar, no grains, low starch is overall a very low carbohydrate diet and it is a very specific dietary change that research suggests can lead to rapid results for blood pressure, especially in those who are overweight or have metabolic issues. The thing to note is thousands of people have done this over decades, it is not anything new. It is important to get advice from your doctor before changing medication.

Here is a reasonable estimate based on the mechanism of action:

Estimated Timeline for Medication Adjustment:

For a significant carbohydrate restriction (ketogenic/very low-carb diet of, for example, less than 40g per day), the initial blood pressure drop is often very quick.

Timeframe	Expected Change & Reason
Days 1–7	Rapid Initial Drop: A low-carb diet is naturally diuretic, meaning the body excretes excess water and sodium quickly. This rapid reduction in fluid volume immediately lowers blood pressure.
Weeks 2–4	First Window for Adjustment: Many studies show that blood pressure begins to fall significantly within the first few weeks. The doctor may need to consider reducing diuretic (water pill) medication first, if any is being taken, as the diet is already doing the job.
1–2 Months	Sustained Drop & Primary Adjustment Window: This is the most common time frame for significant, measurable improvement. By now, the inflammation should be reduced, insulin sensitivity improved, and weight loss should be noticeable. The doctor may consider reducing or discontinuing other antihypertensive medications (like ACE inhibitors or calcium channel blockers).
2–6 Months	Full Stabilisation: If the blood pressure remains stable and low, this is the window where the patient might achieve the maximum possible reduction in their medication, or potentially stop it entirely, depending on their original hypertension severity.

Why the Change is So Potent (The Mechanisms)

The specific change you outlined (no refined sugar, no grains, no high-starch foods, under 40g carbs) is highly effective because it addresses several root causes of hypertension simultaneously:

1. Diuresis (Rapid): Restricting carbohydrates leads to the depletion of glycogen stores, which hold water and sodium. This flush of fluid is the fastest way to drop blood pressure.
2. Improved Insulin Sensitivity: High carbohydrate/sugar intake raises insulin. High insulin contributes to hypertension by causing the kidneys to retain salt and water. The low-carb diet directly reduces insulin, which helps the body naturally regulate fluid balance.
3. Reduced Inflammation: Removing refined sugars and grains, which can be inflammatory, and replacing them with whole, nutrient-dense foods reduces systemic inflammation, leading to healthier, more flexible blood vessel walls.
4. Weight Loss: Weight loss is one of the most powerful non-drug treatments for hypertension, and this type of diet often leads to significant, fast weight loss.

The Key Role of Monitoring Changes:

It is vital to monitor blood pressure closely at home. A sudden, large drop in blood pressure (hypotension) while on medication can cause lightheadedness, dizziness, and fainting.

Doing this method should involved reporting low or falling readings to your doctor when they happen, as the doctor will use this data to safely begin a de-prescribing protocol (stopping or reducing medications, often one at a time).