Weight loss of 5 to 10% demonstrably lowers blood pressure by several mmHg and modestly improves HDL cholesterol. The effect on LDL cholesterol depends on the diet type: a low-fat diet helps the most here. However, the gains are not self-evidently permanent: without sustained weight loss, the benefits largely fade after one year, with the exception of the Mediterranean diet, which holds up for longer.
Losing weight has a clear and measurable positive effect on blood pressure. With an average weight loss of 5 kilograms, systolic blood pressure drops by approximately 4 to 5 mmHg and diastolic blood pressure by 3 to 4 mmHg. The more weight you lose, the greater this effect. This also applies to older adults with high blood pressure: weight loss through diet and exercise helps, and the effect is further strengthened by additional measures such as reducing salt or following the DASH or Mediterranean diet.
The effect on cholesterol is more nuanced and depends strongly on the type of diet you follow. A low-fat diet lowers LDL cholesterol (the 'bad' cholesterol) the most, by an average of approximately 7 mg/dL. A low-carbohydrate diet barely lowers LDL (only 1 mg/dL), but slightly raises HDL cholesterol (the protective cholesterol). The good news is that weight loss of 5 to 10% improves HDL cholesterol with most diet types, although that effect is modest.
An important point to keep in mind is how long the results last. The improvements in blood pressure and cholesterol that are visible after six months largely disappear after twelve months with most diets, probably because some of the weight is regained by then. The Mediterranean diet is an exception to this: it proved able to sustain its benefits for blood pressure and cholesterol for longer.
In people who use medication to assist with weight loss, the blood pressure effects have been well studied. Tirzepatide (a combined GLP-1/GIP agent) reduced systolic blood pressure after 72 weeks by nearly 7 mmHg and diastolic blood pressure by more than 4 mmHg compared with a placebo; 68 to 71% of that effect was directly attributable to the weight loss itself. Semaglutide (a GLP-1 agent) showed a similar picture: nearly 5 mmHg reduction in systolic blood pressure, and people were able to reduce their blood-pressure-lowering medication more often. Note: with tirzepatide, low blood pressure (hypotension) occurred more frequently than with placebo, although it was rare.
Finally, there is an early indication that meal timing matters. An analysis of 12 small studies found that early time-restricted eating, in which the eating window is placed in the morning and early afternoon, improves blood pressure and insulin sensitivity more than eating later in the day or having no time restriction at all. This is an interesting finding, but the evidence is preliminary and requires confirmation in larger studies.
Based on 8 claims with PMIDs: 28455679, 12975389, 32238384, 39084707, 39217502, 39505584, 36702768. Studies include meta-analyses, large RCTs (tirzepatide, semaglutide) and a small systematic review of time-restricted eating (n=12 studies). Blood pressure effects are the best supported; cholesterol effects are more diet-dependent and moderately supported.