Health Evidence Library
Curated research from trusted sources. Transparent. Cited. Always free.
9 records in the library
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Do ultra-processed foods cause weight gain?
Hall KD et al. · Cell Metabolism · 2019
One tightly controlled National Institutes of Health trial showed that an ultra-processed diet caused people to eat more and gain weight over two weeks. That is real causal evidence. It is also one small, short study, so it cannot tell us which ingredient or processing feature caused the difference. The useful next step is to replace the foods that make it easiest to eat fast and keep eating, not to treat every packaged food as the same problem.
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How do loneliness and social connection affect health?
Holt-Lunstad J et al. · Perspectives on Psychological Science · 2015
Loneliness and social isolation are consistently linked with worse physical and mental health. The link is important, but it is not as simple as saying loneliness directly causes every illness associated with it. Health can weaken social connection, and weak social connection can make health harder to protect. Start by naming what is missing: more contact, more supportive relationships, or help with a health problem that makes connection difficult.
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How much sleep do adults need?
Watson NF et al. · Journal of Clinical Sleep Medicine · 2015
Most adults should regularly get at least 7 hours of sleep each night. That is a health recommendation, not a promise that exactly 7 hours is right for every person. Some adults need more, and sleep quality matters along with time asleep. If you get enough time in bed but still wake exhausted, the next step is to look for the reason instead of simply adding another hour.
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How much strength training do adults need?
U.S. Department of Health and Human Services · U.S. Department of Health and Human Services · 2018
Federal guidelines recommend muscle-strengthening activity for all major muscle groups at least 2 days each week. You do not need a bodybuilding routine for it to count. Weights, resistance bands, body-weight exercises, carrying heavy loads, and heavy gardening can all qualify when they make the muscles work harder than usual.
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Do omega-3 fatty acid supplements reduce symptoms of depression?
Appleton KM et al. · Cochrane Database of Systematic Reviews · 2021
The evidence is mixed. Some meta-analyses of randomized trials find a modest reduction in depression symptoms with omega-3 supplementation, particularly formulations high in EPA, while the most rigorous Cochrane systematic review found the evidence overall is low to moderate certainty and any benefit, if real, appears to be small.
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Does following a Mediterranean diet reduce the risk of dying from any cause?
Sofi F et al. · BMJ · 2008
Yes, with strong and consistent support. People who more closely follow a Mediterranean-style diet, rich in vegetables, fruit, whole grains, legumes, olive oil, and fish, with limited red and processed meat, have a lower risk of dying from any cause over long-term follow-up compared with people who follow it less closely.
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Does time-restricted eating improve metabolic health?
Sutton EF et al. · Cell Metabolism · 2018
Short-term evidence suggests time-restricted eating, especially eating earlier in the day within a 6- to 10-hour window, may improve insulin sensitivity, blood pressure, and some cardiometabolic markers, sometimes even without weight loss. Evidence for meaningful long-term weight loss specifically is more mixed, and larger, longer trials are still needed.
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Does vitamin D supplementation reduce the risk of acute respiratory infections?
Martineau AR et al. · The BMJ · 2017
Evidence suggests vitamin D supplementation modestly reduces the risk of acute respiratory tract infections overall, with the clearest benefit in people who are vitamin D deficient at baseline and in those taking daily or weekly doses rather than large infrequent bolus doses.
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Is high-intensity interval training (HIIT) better than moderate-intensity continuous training for cardiovascular health?
Weston KS et al. · British Journal of Sports Medicine · 2014
In people with existing cardiometabolic disease, HIIT produces a larger improvement in cardiorespiratory fitness (VO2peak) than moderate-intensity continuous training (MICT) of similar time commitment, with a comparable safety profile in supervised settings. For the general population without existing disease, evidence suggests both approaches meaningfully improve cardiovascular health, and consistency matters more than which one is chosen.