Intermittent fasting has a solid track record for taking weight off, and a 2025 meta‑analysis in Nutrition Journal shows it does more than that. Pooling 15 randomized trials of overweight and obese adults, the researchers found fasting reliably lowered body weight, BMI, diastolic blood pressure and LDL cholesterol. It also did something people don't expect: it pushed triglycerides up, at least early on. That one counterintuitive number is the best argument in the whole paper for not doing this blind. A marker drifting the wrong way for the right reason is exactly what makes people abandon a plan that's working. Reading your results in context, and keeping you on track through them, is what Omadic's licensed nurses are for.
What the analysis pooled
The review gathered 15 randomized controlled trials covering 758 overweight and obese adults, ages 32 to 65, who fasted for somewhere between 6 and 16 weeks. Following standard systematic‑review methods, the authors searched the major medical databases through March 2025 and included the full range of approaches: time‑restricted eating, alternate‑day fasting, the 5:2 and 4:3, and intermittent calorie restriction, each compared against a normal‑eating control. The trials varied a good deal in how they ran, which is common in this field and part of why the authors end up arguing for fasting that's tailored to the individual rather than applied off a template.
The body‑composition wins
The weight results were the strongest part. Across the trials, fasting took off about 3.73 kg more than the control diets and dropped BMI by just over a full point, both with very high statistical confidence. The longer people stuck with it, the better it got: in trials that ran past 12 weeks, the weight loss grew to roughly 4.67 kg. Among the methods, alternate‑day fasting led at about 4.43 kg.
Not everything moved. Waist circumference trended down by about 2.42 cm but didn't reach statistical significance, and waist‑to‑hip ratio barely changed. The headline is still clear: fasting is a dependable way to lose weight, and it works better the longer you keep at it. A drop of three to five kilograms, with more on the table over time, is the kind of change that meaningfully lowers the health risks tied to carrying extra weight.
The heart‑health markers
The cardiovascular picture was mostly encouraging. Diastolic blood pressure, the lower number, fell by about 3.3 mmHg, a statistically significant drop. Systolic pressure trended down too, though not enough to reach significance on its own. Total cholesterol came down by around 6.3 mg/dL and LDL, the "bad" cholesterol, by about 5.4 mg/dL, both significant. Alternate‑day fasting again did the most for LDL, cutting it by nearly 9 mg/dL. Reductions of that size won't replace a statin for someone who genuinely needs one, but as a free byproduct of changing when you eat, they nudge two of the numbers most closely tied to heart‑disease risk in the right direction.
A few markers held flat. HDL cholesterol didn't move, and fasting glucose and HbA1c didn't shift much in this group. That tracks with who was studied: overweight adults who were generally not diabetic, so there was less dysfunction to correct, and the authors note the body's hormonal counter‑responses can blunt the glucose effect early on. They also flag that the trials didn't include enough higher‑risk participants to say how blood sugar responds in people with diabetes or metabolic syndrome. Other research in that group is more encouraging on the glucose front, which we covered separately. (More on fasting and metabolic syndrome here.)
The triglyceride surprise
Here's the part that catches people off guard. Triglycerides, a blood fat you'd expect to fall with weight loss, went up instead, by about 8.56 mg/dL on average across the trials. The increase was sharper in the short‑term studies, around 13 mg/dL in trials of 12 weeks or less.
It sounds alarming until you see the mechanism. When you first start fasting, your body begins pulling stored fat out for fuel, which floods the bloodstream with free fatty acids. The liver packages a lot of those into triglycerides faster than your metabolism has adapted to clearing them, so the number on your lab report climbs for a while. That climbing number marks fat being burned for energy, and it reflects the diet doing its job even though it looks like the opposite. The rise was smaller in the longer trials than the short ones, which fits the idea of the body adapting as fasting continues, though the studies weren't long enough to show triglycerides fully settling back.
Now picture seeing that result on your own, with no context. You've been doing everything right, the scale is moving, and then your triglycerides come back higher than when you started. A lot of people would assume fasting is hurting them and quit. That's the moment a generic fasting app leaves you alone with a confusing number. It's also the moment a professional makes the difference.
Why this is the case for a professional
A licensed nurse reads that triglyceride bump for what it usually is: an early adaptation, not an emergency. They look at the whole panel, weight down, LDL down, blood pressure down, and put one rising marker in proportion. They know whose triglyceride response actually warrants a closer look and whose doesn't, and they can tell the expected early rise from a real red flag that belongs in front of your doctor.
Every Omadic plan is overseen by licensed nurses and health professionals. They set the fasting approach to your body and your goals, watch how your markers move over time, and explain what you're seeing instead of leaving you to interpret a lab report alone. If you take medication for blood pressure or cholesterol, they factor it in and coordinate with your prescriber. Someone who already runs high on triglycerides, or who's on a statin, gets watched more closely from the start, and the plan flexes to fit the history rather than ignoring it. The authors of this very review call for fasting that is "precise and sustainable" and built around the individual. A nurse‑guided plan is what that looks like in practice.
The longer you stay with it, the better it reads
The most consistent thread in the data is that time helps. Weight loss was larger in the longer trials, and the triglyceride rise was smaller in them. The authors are also upfront that most of the studies were short, 12 weeks or less, and that fasting's long‑term benefits still need bigger and longer trials to confirm. The early weeks are when the markers are noisiest and when people are most likely to give up. Getting through that adjustment, with someone who can tell you which wobbles are normal, is how a promising few weeks become a lasting result. The authors point to adherence as one of fasting's biggest advantages over conventional dieting, and adherence is exactly the thing a guided program is built to protect.
How Omadic puts it to work
- Guided fasting matched to you, starting gentle and progressing as your body adapts, with the method chosen for your goals rather than a one‑size plan.
- Markers tracked over time, so a single odd reading is read against the whole trend instead of in isolation.
- Medication and supplement reminders and coordination with your prescriber if you take anything for blood pressure, cholesterol or blood sugar.
- Licensed‑nurse coaching through all of it, especially during the early weeks when your bloodwork is still settling.
Fasting clearly works for weight and for several markers of heart health. The wrinkles, like a temporary rise in triglycerides, are manageable when someone who understands them is watching. Real results paired with real oversight is what Omadic was built to deliver.
Common questions
Does intermittent fasting raise triglycerides? It can, at least early on. This 2025 review of 15 trials found triglycerides rose by about 8.56 mg/dL on average, and more in short‑term studies, as the body mobilizes stored fat faster than it adapts to clearing it. The rise was smaller in longer trials than short ones, and it sits alongside drops in weight, LDL cholesterol and diastolic blood pressure. It's worth reviewing with a professional rather than panicking over.
Does intermittent fasting lower cholesterol and blood pressure? In this analysis, yes. Total cholesterol fell by about 6.3 mg/dL and LDL by about 5.4 mg/dL, both significant, and diastolic blood pressure dropped by around 3.3 mmHg. HDL didn't change much. Alternate‑day fasting had the strongest effect on LDL.
How much weight can intermittent fasting take off? The pooled average was about 3.73 kg compared with normal eating, rising to roughly 4.67 kg in trials longer than 12 weeks. Alternate‑day fasting led the methods at about 4.43 kg. As with most things in fasting, staying consistent over time did more than going hard in a short burst.
Which type of intermittent fasting works best here? Alternate‑day fasting produced the biggest reductions in both weight and LDL in this review. It's also the most demanding to keep up, so the right method is still the one you can sustain. (Omadic starts most people on time‑restricted eating and adjusts from there.)
Will intermittent fasting reduce belly fat? Indirectly, through overall weight loss, and this review is a useful reality check. While weight and BMI dropped clearly, the change in waist circumference (about 2.42 cm) didn't reach statistical significance, partly because tape measurements are less precise than the scale. Expect the scale to move first; waistline changes tend to follow as the weight loss adds up.
Is the triglyceride increase dangerous? For most people it appears to be part of early adaptation to fasting rather than a warning sign, and it was largest in the shorter trials. If you already have high triglycerides or heart disease, it's worth tracking with a professional who can tell a normal adjustment from a result that needs attention.
New to fasting? Start with how to break a fast the right way and why electrolytes matter on longer fasts.
Sources
- Wang B, Wang C, Li H. The impact of intermittent fasting on body composition and cardiometabolic outcomes in overweight and obese adults: a systematic review and meta‑analysis of randomized controlled trials. Nutrition Journal. 2025;24:120. Read the study (Nutrition Journal) · Full text (PubMed Central)
- de Cabo R, Mattson MP. Effects of Intermittent Fasting on Health, Aging, and Disease. New England Journal of Medicine, 2019.