High fat diet, cholesterol and heart disease

Following our 8 golden rules dietary advice means incorporating high fat into the diet as fat helps slow down the release of glucose from carbs into the bloodstream and helps you to feel fuller for longer. For many this rings alarm bells! Fat = getting fat!

You have just been diagnosed with a condition which means your baby could be, or may grow to be much bigger than it should and now you're reading that we advocate incorporating fat into the diet? What planet are we on?!

Surely eating lots of fat is just going to cause more problems and leave us fatter, cause our babies to grow bigger, giving us high cholesterol and lead to heart disease? Eating fat is just plain unhealthy, right? Well that's what we've been told for many years, however lots of research is now telling us differently...


Understanding the difference between fats

There are different types of fats. Unsaturated fats such as monounsaturated fats and polyunsaturated fats which include omega-3 and omega-6 fatty acids and are known as being the 'good fats'. These include things like olives, olive oil, oily fish, avocado and nuts.

These fats improve blood cholesterol levels and can decrease your risk of heart disease.  They also play an important role in the development of the brain, eyes and nervous system of your growing baby and so are essential for baby's growth.

There are then the saturated fats which are the ones which are now being disputed. For years, saturated fats have been thought to be the bad fats, however this is based on information from the 70's and 80's and is now being challenged as research suggests saturated fats are not the evil fat they've been labelled. Saturated fats can be found in many foods like butter, cheese, cream, milk, fatty cuts of meat, the skin on chicken, lard, suet, and coconut oil.

Lastly, there are the trans fats, these are undoubtedly bad fats which should be avoided or eaten in very small amounts. You can read more about trans fats towards the end of this article.

The truth about fat revolution


Worried about weight gain

Many ladies first concern after years of following low fat dietary advice is that a higher fat diet is going to cause weight gain. This is something that is still drummed into advice from all over and more so than ever when pregnant, as high weight gain during pregnancy should be avoided. We also need to avoid weight gain with it increasing the risk of type 2 diabetes, in the knowledge that women diagnosed with gestational diabetes are already at a higher risk.

This is what we have found in women following our low carb, high fat GD UK dietary advice during their GD pregnancy:

In a survey we conducted in 2018 with 1,185 responses, 62% of women LOST weight and 23% stayed the same weight (thus meaning they lost weight as they were the same weight as the beginning of their pregnancy, yet had the weight of baby, placenta and fluid etc.) This means that we have seen a huge 85% of women LOSE weight eating a higher fat diet!

Not only did a majority lose weight, but their blood sugar levels were lowered and stabilised, they felt healthier and better than before too!

Some of the Research

To truly understand what has been researched and understand why saturated fats are now being disputed then it is best to look into some of the findings of more recent research: -

A Systematic Review of the Evidence Supporting a Causal Link Between Dietary Factors and Coronary Heart Disease

Results Strong evidence supports valid associations (4 criteria satisfied) of protective factors, including intake of vegetables, nuts, and “Mediterranean” and high-quality dietary patterns with CHD, and associations of harmful factors, including intake of trans–fatty acids and foods with a high glycemic index or load. Among studies of higher methodologic quality, there was also strong evidence for monounsaturated fatty acids and “prudent” and “western” dietary patterns. Moderate evidence (3 criteria) of associations exists for intake of fish, marine ω-3 fatty acids, folate, whole grains, dietary vitamins E and C, beta carotene, alcohol, fruit, and fiber. Insufficient evidence (≤2 criteria) of association is present for intake of supplementary vitamin E and ascorbic acid (vitamin C); saturated and polyunsaturated fatty acids; total fat; α-linolenic acid; meat; eggs; and milk. Among the dietary exposures with strong evidence of causation from cohort studies, only a Mediterranean dietary pattern is related to CHD in randomized trials.

Conclusions The evidence supports a valid association of a limited number of dietary factors and dietary patterns with CHD. Future evaluation of dietary patterns, including their nutrient and food components, in cohort studies and randomized trials is recommended.

Meta-analysis of prospective cohort studies evaluating the association of saturated fat with cardiovascular disease

Results: During 5–23 y of follow-up of 347,747 subjects, 11,006 developed CHD or stroke. Intake of saturated fat was not associated with an increased risk of CHD, stroke, or CVD.

Conclusions: A meta-analysis of prospective epidemiologic studies showed that there is no significant evidence for concluding that dietary saturated fat is associated with an increased risk of CHD or CVD. More data are needed to elucidate whether CVD risks are likely to be influenced by the specific nutrients used to replace saturated fat.

The relationship between high-fat dairy consumption and obesity, cardiovascular, and metabolic disease


The observational evidence does not support the hypothesis that dairy fat or high-fat dairy foods contribute to obesity or cardiometabolic risk, and suggests that high-fat dairy consumption within typical dietary patterns is inversely associated with obesity risk. Although not conclusive, these findings may provide a rationale for future research into the bioactive properties of dairy fat and the impact of bovine feeding practices on the health effects of dairy fat.

Evidence from prospective cohort studies does not support current dietary fat guidelines: a systematic review and meta-analysis


Across 7 studies, involving 89 801 participants (94% male), there were 2024 deaths from CHD during the mean follow-up of 11.9±5.6 years. The death rate from CHD was 2.25%. Eight data sets were suitable for inclusion in meta-analysis; all excluded participants with previous heart disease. Risk ratios (RRs) from meta-analysis were not statistically significant for CHD deaths and total or saturated fat consumption. The RR from meta-analysis for total fat intake and CHD deaths was 1.04 (95% CI 0.98 to 1.10). The RR from meta-analysis for saturated fat intake and CHD deaths was 1.08 (95% CI 0.94 to 1.25).


Epidemiological evidence to date found no significant difference in CHD mortality and total fat or saturated fat intake and thus does not support the present dietary fat guidelines. The evidence per se lacks generalisability for population-wide guidelines.

Associations of fats and carbohydrate intake with cardiovascular disease and mortality in 18 countries from five continents (PURE): a prospective cohort study

The Prospective Urban Rural Epidemiology (PURE) study is a large, epidemiological cohort study of individuals aged 35–70 years (enrolled between Jan 1, 2003, and March 31, 2013) in 18 countries with a median follow-up of 7·4 years (IQR 5·3–9·3). Dietary intake of 135 335 individuals was recorded using validated food frequency questionnaires. The primary outcomes were total mortality and major cardiovascular events (fatal cardiovascular disease, non-fatal myocardial infarction, stroke, and heart failure). Secondary outcomes were all myocardial infarctions, stroke, cardiovascular disease mortality, and non-cardiovascular disease mortality. Participants were categorised into quintiles of nutrient intake (carbohydrate, fats, and protein) based on percentage of energy provided by nutrients. We assessed the associations between consumption of carbohydrate, total fat, and each type of fat with cardiovascular disease and total mortality. We calculated hazard ratios (HRs) using a multivariable Cox frailty model with random intercepts to account for centre clustering.


During follow-up, we documented 5796 deaths and 4784 major cardiovascular disease events. Higher carbohydrate intake was associated with an increased risk of total mortality (highest [quintile 5] vs lowest quintile [quintile 1] category, HR 1·28 [95% CI 1·12–1·46], p trend=0·0001) but not with the risk of cardiovascular disease or cardiovascular disease mortality. Intake of total fat and each type of fat was associated with lower risk of total mortality (quintile 5 vsquintile 1, total fat: HR 0·77 [95% CI 0·67–0·87], p trend<0·0001; saturated fat, HR 0·86 [0·76–0·99], p trend=0·0088; monounsaturated fat: HR 0·81 [0·71–0·92], p trend<0·0001; and polyunsaturated fat: HR 0·80 [0·71–0·89], p trend<0·0001). Higher saturated fat intake was associated with lower risk of stroke (quintile 5 vs quintile 1, HR 0·79 [95% CI 0·64–0·98], p trend=0·0498). Total fat and saturated and unsaturated fats were not significantly associated with risk of myocardial infarction or cardiovascular disease mortality.


High carbohydrate intake was associated with higher risk of total mortality, whereas total fat and individual types of fat were related to lower total mortality. Total fat and types of fat were not associated with cardiovascular disease, myocardial infarction, or cardiovascular disease mortality, whereas saturated fat had an inverse association with stroke. Global dietary guidelines should be reconsidered in light of these findings.

Lack of an association or an inverse association between low-density-lipoprotein cholesterol and mortality in the elderly: a systematic review

Results We identified 19 cohort studies including 30 cohorts with a total of 68 094 elderly people, where all-cause mortality was recorded in 28 cohorts and CV mortality in 9 cohorts. Inverse association between all-cause mortality and LDL-C was seen in 16 cohorts (in 14 with statistical significance) representing 92% of the number of participants, where this association was recorded. In the rest, no association was found. In two cohorts, CV mortality was highest in the lowest LDL-C quartile and with statistical significance; in seven cohorts, no association was found.

Conclusions High LDL-C is inversely associated with mortality in most people over 60 years. This finding is inconsistent with the cholesterol hypothesis (ie, that cholesterol, particularly LDL-C, is inherently atherogenic). Since elderly people with high LDL-C live as long or longer than those with low LDL-C, our analysis provides reason to question the validity of the cholesterol hypothesis. Moreover, our study provides the rationale for a re-evaluation of guidelines recommending pharmacological reduction of LDL-C in the elderly as a component of cardiovascular disease prevention strategies.

Association of Dietary, Circulating, and Supplement Fatty Acids With Coronary Risk: A Systematic Review and Meta-analysis

Data Synthesis:

There were 32 observational studies (512 420 participants) of fatty acids from dietary intake; 17 observational studies (25 721 participants) of fatty acid biomarkers; and 27 randomized, controlled trials (105 085 participants) of fatty acid supplementation. In observational studies, relative risks for coronary disease were 1.03 (95% CI, 0.98 to 1.07) for saturated, 1.00 (CI, 0.91 to 1.10) for monounsaturated, 0.87 (CI, 0.78 to 0.97) for long-chain ω-3 polyunsaturated, 0.98 (CI, 0.90 to 1.06) for ω-6 polyunsaturated, and 1.16 (CI, 1.06 to 1.27) for trans fatty acids when the top and bottom thirds of baseline dietary fatty acid intake were compared. Corresponding estimates for circulating fatty acids were 1.06 (CI, 0.86 to 1.30), 1.06 (CI, 0.97 to 1.17), 0.84 (CI, 0.63 to 1.11), 0.94 (CI, 0.84 to 1.06), and 1.05 (CI, 0.76 to 1.44), respectively. There was heterogeneity of the associations among individual circulating fatty acids and coronary disease. In randomized, controlled trials, relative risks for coronary disease were 0.97 (CI, 0.69 to 1.36) for α-linolenic, 0.94 (CI, 0.86 to 1.03) for long-chain ω-3 polyunsaturated, and 0.86 (CI, 0.69 to 1.07) for ω-6 polyunsaturated fatty acid supplementations.


Current evidence does not clearly support cardiovascular guidelines that encourage high consumption of polyunsaturated fatty acids and low consumption of total saturated fats.

Effects of low-carbohydrate diets v. low-fat diets on body weight and cardiovascular risk factors: a meta-analysis of randomised controlled trials

The effects of low-carbohydrate (LC) diets on body weight and cardiovascular risk are unclear, and previous studies have found varying results. Our aim was to conduct a meta-analysis of randomised controlled trials (RCT), assessing the effects of LC diets v. low-fat (LF) diets on weight loss and risk factors of CVD. Studies were identified by searching MEDLINE, Embase and Cochrane Trials. Studies had to fulfil the following criteria: a RCT; the LC diet was defined in accordance with the Atkins diet, or carbohydrate intake of <20 % of total energy intake; twenty subjects or more per group; the subjects were previously healthy; and the dietary intervention had a duration of 6 months or longer. Results from individual studies were pooled as weighted mean difference (WMD) using a random effect model. In all, eleven RCT with 1369 participants met all the set eligibility criteria. Compared with participants on LF diets, participants on LC diets experienced a greater reduction in body weight (WMD –2·17 kg; 95 % CI –3·36, –0·99) and TAG (WMD –0·26 mmol/l; 95 % CI –0·37, –0·15), but a greater increase in HDL-cholesterol (WMD 0·14 mmol/l; 95 % CI 0·09, 0·19) and LDL-cholesterol (WMD 0·16 mmol/l; 95 % CI 0·003, 0·33). This meta-analysis demonstrates opposite change in two important cardiovascular risk factors on LC diets – greater weight loss and increased LDL-cholesterol. Our findings suggest that the beneficial changes of LC diets must be weighed against the possible detrimental effects of increased LDL-cholesterol.

Other sources worth looking at:

The Public Health Collaboration - check out this document which you can download and print. It contains tons of research and information which will help you, your family, friends and health care professionals understand more about following a low carb, higher fat diet

Diet Doctor - This website can provide TONS of information around the benefits around following a low carb, high fat diet. This article discusses cholesterol and high fat diet.

The Disputed Science on Saturated Fats

The fats to avoid, trans fats

There are still some types of fat to avoid as these are the type that are undisputedly bad for you. These are trans fats and are the type of fat that is found in highly processed foods. Here are some examples of where higher transfats may be found:

  • Cakes and doughnuts
  • Biscuits
  • Crackers
  • Margarine
  • Frozen pizza
  • Ready meals
  • Fried takeaway food
  • Crisps
  • Vegetable and seed oils
  • Pies and pastries
  • Microwave popcorn
  • Elmlea artificial cream

The key message to take away

Real food, natural sources of fat should not be feared and can help with controlling blood sugar levels, obesity and will not make your arteries clogged causing heart disease.

Always pick REAL FOOD over processed - Know what you are putting in your body!